Patent Application
20230416329
The present invention belongs to the field of biological medicine technology, and relates to a peptide with the inhibitory activity against metabolic serine hydrolases (e.g., trypsin, chymotrypsin and elastase), or its analog having N-terminal, C-terminal, or side chain modified by PEGylation, phosphorylation, amidation or acylation, or a pharmaceutically acceptable salt thereof. Particularly, the present invention also relates to an application of active peptides with inhibitory activity against serine proteases. These peptides, their pegylated, phosphorylated, amideated or acylated analogues or pharmaceutically acceptable salts are fused with proteins, peptides or glycoproteins with therapeutic activities. They form hybrid peptides by N- or C-terminal fusion or insertion into those proteins or peptides. The hybrid polypeptides still maintain the activities of inhibiting serine proteases, thus improving the stability and efficacy of in vivo administration the of therapeutic proteins and peptides.
Bioactive proteins and peptides have been widely used to treat a variety of chronic and potentially life-threatening diseases such as cancer, inflammatory diseases and diabetes. The bindings between proteins and peptides with their targets are specific, namely they are of highly specific interactions with target molecules, and low specificity for non-target molecules. Long-term administration of proteins and peptides can also show low accumulation in tissues, thus reducing the side effects of the drugs. In addition, peptides are metabolized into constituent amino acids in vivo, thus reducing the risk of complications caused by toxic metabolic intermediates. At present, due to the low bioavailability caused by the stability of protein and peptide in the gastrointestinal tract and the absorption barrier related to molecular size, the subcutaneous or intravenous administration of protein and peptide drugs is still the most widely used route of administration. Although the widely used and convenient oral administration is particularly attractive to patients, there are two major obstacles that gastrointestinal the hydrolysis of gastrointestinal digestive enzymes and the low permeability of intestinal epithelial cells need to be overcome1,2.
To solve the challenges related to the oral delivery of proteins and peptides, such as the stability in the gastrointestinal tract and the low-permeability absorption across the epithelial cell layer of the small intestine, many pharmaceutical technologies of oral formulations have been developed including absorption enhancers, protease inhibitors and degradable carrier materials, etc. They are helpful for overcoming the problems of protease degradation and osmotic absorption barrier in combine with enteric coating and nanoparticle technology.
The intestinal villus absorption surface of an adult is nearly 200 m2, which is responsible for the absorption and transport of up to 90% nutrients in the body. Therefore, the microanatomy structure and physiological function of the small intestine indicate that it is the most ideal release position for oral delivery of protein and peptide drugs. The use of enteric-coated drug delivery system can avoid enzymatic degradation of biological drugs when they pass through the stomach and directly reach the small intestine for absorption. There is high concentration of proteolytic enzymes secreted by the pancreas or small intestinal mucosal cells in the lumen of the small intestine, which is another problem of oral administration of biological drugs. The key to obtain drugs with appropriate oral activity is to protect therapeutic proteins and peptides from proteolytic hydrolysis in the lumen of the small intestine.
In recent research reports, the application of many trypsin and chymotrypsin inhibitors, such as soybean trypsin inhibitor, pancreatic protease inhibitor and aprotinin, reduces the degradation effect of these enzymes and improves the oral bioavailability of insulin3.
Due to the low toxicity and strong inhibitory activity against peptide protease inhibitors, polypeptide protease inhibitors have so far been used to the highest extent as auxiliary agents to overcome the enzymatic barrier of perorally administered therapeutic peptides and proteins. Among these peptide protease inhibitors, a Bowman-Birk inhibitor (BBI) inhibitor of soybean trypsin inhibitor family with two inhibitory loops, is known to inhibit human trypsin as well as chymotrypsin. Moreover, these protease inhibitors of BBI family also showed inhibitory activity against elastase. This circumstance of their multiple functions is completely accord with multiple proteolytic events of the pancreatic enzymes. Therefore, these protease inhibitors have been widely used as inhibitors of therapeutic proteins and peptides against protease hydrolysis, which were publicly described in Patent Cooperation Treaty (PCT) patents WO2014191545, WO2019239405 and WO2017161184.
Compared with BBI inhibitor, sunflower trypsin inhibitor 1 (SFTI-1) is a cyclic peptide isolated from sunflower seeds that contains only 14 amino acid residues. It can be used as a protease inhibitor, an oral drug component for the treatment of diabetes, as described in PCT WO2020023386. SFTI-1 is head-tail cyclized to form a rigid structure, including two short D-folding, one intramolecular disulfide bond. These structural characteristics help to stabilize the protease inhibitory active loop of SFTI-1, which forms the molecular structure basis of its extremely strong inhibitory activity against trypsin (Ki<0.1 nM)4. SFTI-1 has been successfully used to engineer inhibitors for an increasing number of protease therapeutic targets, including cancer-related protease inhibitors such as matriptase5, 6, metorypsin7 and kallikrein associated protease 4 (KLK4)8, 9. SFTI-1 has also been used to engineer the protease inhibitor related to skin diseases, including KLK510, 11, 12, 13 and KLK714. In addition, SFTI-1 mutants have been designed as protease inhibitors towards matriptase-2 involving in iron overload disorders15, subtilisin-like protease furin16, cathepsin G implicated in chronic inflammation17,18, specific neutrophil-like elastase-like protease 319, plasmin implicated in fibrinolysis20 and chymase21. Besides these, the very small size and high proteolytic stability of SFTI-1 have made it an excellent scaffold for protein engineering in which peptide fragments with completely novel function can be grafted into the SFTI-1 framework, for engineering radiotherapeutics22, pro-angiogenic compounds23, bradykinin B1 receptor antagonist24, Melanocortin receptor agonists25, and other peptide segments derived from annexin A1, α-fibrinogen epitopes and CD2 adhesion domain can be grafted into SFTI-1 scaffold for the treatment of inflammatory bowel diseases (IBDs)26 and rheumatoid arthritis27,28. However, the peptide length of these engineered protease inhibitory loops or grafted active epitopes is limited to less than 10 amino acid residues. SFTI-1 framework can't tolerate the grafting of length peptide of more than 10 amino acid residues (e.g. glucagon-like peptide-1, 30 aa) or proteins (e.g. antibodies).
The polypeptide protease inhibitors and biopharmaceuticals can be encapsulated into nanoparticle system at the same time, which can effectively protect them from enzymatic degradation and improve the intestinal absorption of polypeptide proteins and peptides. However, one of the major disadvantages of these inhibitors is that they have high toxicity, especially in the long-term use of the drug. And inhibition of protease inhibitors in the gastrointestinal tract may interfere with normal digestion and absorption of protein, causing reversible or even irreversible structural and functional damage to it. What's more, polypeptide protease inhibitors are specific and only play a role at a certain time and at certain sites. And biopharmaceuticals and polypeptide protease inhibitors must simultaneously pass through the metabolic sites. Moreover, the use of polypeptide protease inhibitors may increase the number of the intact drug at the absorption site but will not help passing through biological membranes. The presence of polypeptide protease inhibitors will affect the normal absorption of nutrition in the gastrointestinal tract, and may even generate feedback regulation to stimulate excessive secretion and expression of metabolic enzymes. Long-term treatment will lead to splenic hypertrophy and hyperplasia.
It is accordingly an object of the present invention to provide the disulfide-constrained peptide with inhibitory activities against serine proteases, via simplifying and optimizing the inhibitory loops of polypeptide protease inhibitors of the soybean Bowman-Birk Inhibitor (BBI), sunflower trypsin inhibitor-1 (SFTI-1). The present invention also presents an application of the peptide inhibitors, or its analog having N-terminal, C-terminal, or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, against serine proteases such as trypsin, chymotrypsin or elastase. These peptide inhibitors can be formed hybrid polypeptides by fusion with the therapeutic proteins and peptides. The formed hybrid peptides still maintain the inhibitory activity against trypsin, chymotrypsin or elastase and their tolerance to other metabolic enzymes is also enhanced, and their pharmacological activity in vivo are improved.
In a first aspect, the present invention provides a peptide, or its analog having N-terminal, C-terminal, or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide has a general formula (M):
Xaa6-Xaa5-Xaa4-Xaa3-Xaa2-Xaa1-Xaa1′-Xaa2′-Xaa3′-Xaa4′-Xaa5′-Cys6′-Xaa7′-Xaa8′ (M);
In an embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide with inhibitory activities of serine proteases has a general formula (I):
Cys6-Xaa5-Xaa4-Xaa3-Xaa2-Xaa1-Xaa1′-Xaa2′-Xaa3′-Xaa4′-Xaa5′-Cys6′-Xaa7′ (I);
Hereinafter the amino acid or its residue listed in Table 1 is provided and suitable for the present invention. The abbreviations used herein follow the naming conventions suggested by the IUPAC Commission on the Nomenclature of Organic Chemistry and the IUPAC-IUB Commission on Biochemical Nomenclature.
In a particular embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide is preferably with anti-trypsin activity among its inhibitory activities of serine proteases.
In another particularly preferred embodiment of the present invention, the anti-trypsin peptide or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, is selected from the group consisting of the following sequences: SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 25, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 35, SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 53, SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 57, SEQ ID NO: 60, SEQ ID NO: SEQ ID NO: 67, SEQ ID NO: 69, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 77, SEQ ID NO: 78, and SEQ ID NO: 79.
In another more particularly preferred embodiment of the present invention, the anti-trypsin peptide or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, is selected from the group consisting of the following sequences: SEQ ID NO: 9, SEQ ID NO: 35, SEQ ID NO: 47, SEQ ID NO: 50, SEQ ID NO: 53, SEQ ID NO: 54, SEQ ID NO: 67, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 77, SEQ ID NO: 78 and SEQ ID NO: 79.
In another particular embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide is preferably with anti-chymotrypsin among its inhibitory activities of serine proteases.
In another more particularly preferred embodiment of the present invention, the anti-chymotrypsin peptide or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, is selected from the group consisting of the following sequences: SEQ ID NO: 93, SEQ ID NO: 95, SEQ ID NO: 103, SEQ ID NO: 104, SEQ ID NO: 107, SEQ ID NO: 111 and SEQ ID NO: 112.
In another particular embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide is preferably with inhibitory activity against chymotrypsin-like elastase among its inhibitory activities of serine proteases.
In another more particularly preferred embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide with inhibitory activity against elastase is selected from the group consisting of the following sequences: SEQ ID NO: 140 and SEQ ID NO: 165.
In another embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide with inhibitory activities of serine proteases has a general formula (II):
Xaa4-Cys3-Xaa2-Xaa1-Xaa1′-Xaa2′-Xaa3′-Xaa4′-Xaa5′-Cys6′-Xaa7′-Xaa8′ (II);
In a particular embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide is preferably with anti-trypsin activity among its inhibitory activities of serine proteases.
In another particularly preferred embodiment of the present invention, the anti-trypsin peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, is selected from the group consisting of the following sequences: SEQ ID NO: 45, SEQ ID NO: 65 and SEQ ID NO: 66.
In another particular embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide is preferably with anti-chymotrypsin activity among its inhibitory activities of serine proteases.
In another particularly preferred embodiment of the present invention, the anti-chymotrypsin peptide or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, is selected from the group consisting of the following sequences: SEQ ID NO: 85, SEQ ID NO: 90, SEQ ID NO: 91, SEQ ID NO: 98, SEQ ID NO: 105, SEQ ID NO: 106, SEQ ID NO: 113, SEQ ID NO: 114, SEQ ID NO: 115, SEQ ID NO: 131, SEQ ID NO: 132 and SEQ ID NO: 133.
In another more particularly preferred embodiment of the present invention, the anti-chymotrypsin peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, is selected from the following the group consisting of sequences: SEQ ID NO: 85 and SEQ ID NO: 90.
In another particular embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide is preferably with inhibitory activity against chymotrypsin-like elastase among its inhibitory activities of serine proteases.
In another particularly preferred embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide with inhibitory activity against elastase is selected from the group consisting of the following sequences: SEQ ID NO: 134, SEQ ID NO: 145, SEQ ID NO: 151, SEQ ID NO: 155, SEQ ID NO: 156, SEQ ID NO: 158 and SEQ ID NO: 162.
In another more particularly preferred embodiment, the present invention provides a peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, wherein the peptide with inhibitory activity against elastase is selected from the group consisting of the following sequences: SEQ ID NO: 145, SEQ ID NO: 155 and SEQ ID NO: 156.
In a particular embodiment, the present invention provides peptide inhibitors against serine proteases, in which trypsin, chymotrypsin and elastase are preferable.
The present invention also provides a hybrid peptide, which comprises the peptide inhibiting serine proteases. The peptide, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, was fused to N-terminus or C-terminus of a therapeutical protein or peptide, or inserted into an intramolecular location of a therapeutical protein or peptide to form a hybrid peptide. The hybrid peptide has a general formula selected from the group, consisting of:
B-L-A (III);
A-L-B (IV);
A1-L1-B-L2-A2 (V);
In one aspect, the present invention provides a method for the application of therapeutic glucagon like peptide-1 (GLP-1), or its analog containing N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, which is attached with peptide inhibitors against serine proteases. The hybrid peptide formed with serine protease inhibitor described above, is selected from the group consisting of the following sequences: SEQ ID NO: 194, SEQ ID NO: 195, SEQ ID NO: 196, SEQ ID NO: 197, SEQ ID NO: 198, SEQ ID NO: 199, SEQ ID NO: 200, SEQ ID NO: 201, SEQ ID NO: 202, SEQ ID NO: 203, SEQ ID NO: 204, SEQ ID NO: 205, SEQ ID NO: 206, SEQ ID NO: 207, SEQ ID NO: 208 and SEQ ID NO: 209. The hybrid peptide is applied to treat type II diabetes and/or obesity.
In another aspect, the present invention provides a method for the use of a therapeutically active peptide SEQ ID NO: 210, or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, which is attached with peptide inhibitors against serine proteases. The active peptide has the ability of inhibiting the protein-protein interaction between proprotein convertase subtilisin/kexin type 9 kexin preprotein converting enzyme (PCSK9) and low-density lipoprotein receptor (LDLR) protein. The hybrid peptide formed with protease inhibitor described above is selected from the group consisting of the following sequences: SEQ ID NO: 211, SEQ ID NO: 212, SEQ ID NO: 214, SEQ ID NO: 215, SEQ ID NO: 216, SEQ ID NO: 217, SEQ ID NO: 218, SEQ ID NO:224, SEQ ID NO: 225, SEQ ID NO: 226, SEQ ID NO: 227, SEQ ID NO: 228, SEQ ID NO: 229, SEQ ID NO: 230, SEQ ID NO: 231, SEQ ID NO: 232 and SEQ ID NO: 233. The hybrid peptide is applied to treat familial hypercholesterolemia.
In another aspect, the present invention provides a method for the use of a therapeutically active peptide salmon calcitonin (SEQ ID NO: 234), or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, which is attached with peptide inhibitors against serine proteases. The hybrid peptide formed with protease inhibitor described above is selected from the group consisting of the following sequences SEQ ID NO: 235, SEQ ID NO: 236, and SEQ ID NO: 237. The hybrid peptide is applied to treat bone related diseases and calcium disorders such as osteoporosis and/or osteoarthritis.
In another aspect, the present invention provides a method for the use of a therapeutically active peptide (SEQ ID NO: 238), or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, which is attached with peptide inhibitors against serine proteases. The active peptide has the ability of inhibiting the interaction between IL-17A and IL-17RA, and its hybrid peptide formed with protease inhibitor described above is selected from the group consisting of the following sequences SEQ ID NO: 239, SEQ ID NO: 240, and SEQ ID NO: 241. The hybrid peptide is applied to treat inflammatory diseases, including inflammatory lung disease, asthma, chronic obstructive pulmonary disease, inflammatory bowel disease, arthritis, autoimmune diseases, rheumatoid arthritis, psoriasis, and systemic sclerosis.
The present invention also provides a peptide composition that can contain at least one, two, or three peptides or analogues thereof having the structure shown in Formula (I) or (II), or a pharmaceutically acceptable salt thereof, as well as one or more hybrid peptides, or analogues thereof, or a pharmaceutically acceptable salt thereof.
In a particular embodiment, a hybrid peptide composition comprises of a hybrid therapeutic glucagon-like peptide-1 (GLP-1), or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, which is formed with protease inhibitor described above. Wherein the hybrid peptide is selected from the group consisting of the following sequences: SEQ ID NO: 200, SEQ ID NO: 204, and SEQ ID NO: 208.
In a particular embodiment, a hybrid peptide composition comprises of a hybrid therapeutic active peptide (SEQ ID NO: 210), or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, which is formed with protease inhibitor described above. Wherein the hybrid peptide is selected from the group consisting of the following sequences: SEQ ID NO: 211, SEQ ID NO: 212, SEQ ID NOs: 214-216, SEQ ID NO: 218 and SEQ ID NOs: 224-233.
In a particular embodiment, a hybrid peptide composition comprises of a hybrid therapeutic active peptide salmon calcitonin (SEQ ID NO: 234), or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, which is formed with protease inhibitor described above. Wherein the hybrid peptide is selected from the group consisting of the following sequences: SEQ ID NOs: 235-237.
In another particular embodiment, a hybrid peptide composition comprises of a hybrid therapeutic active peptide (SEQ ID NO: 238), or its analog having N-terminal, C-terminal or side chain modified by PEGylation, phosphorylation, amidation, or acylation, or a pharmaceutically acceptable salt thereof, which is formed with protease inhibitor described above. Wherein the hybrid peptide is selected from the group consisting of the following sequences: SEQ ID NOs: 239-241.
In an aspect, the present invention provides pharmaceutical excipients that can be co administered, further comprising pharmaceutically acceptable carriers, diluents, dispersants, promoters, and/or excipients, to promote the permeation and absorption of biologically active hybrid peptides or a pharmaceutically acceptable salt through the intestinal epithelium.
In another aspect, the present invention provides a method of administration of biologically active hybrid peptides or a pharmaceutically acceptable salt, suitable for injection and/or oral administration.
In an embodiment, the present invention provides a protectively pharmaceutical delivery tool including enteric coated capsules, microcapsules, or particles that effectively transport bioactive hybrid peptides or biological therapeutic agents to the intestinal absorption site, blocking the contact and degradation of bioactive hybrid peptides or a pharmaceutically acceptable salt with pepsin.
In another embodiment, the protease inhibitors, therapeutic oligopeptides, and hybrid peptides in the present invention, SEQ ID NOs: 1-241, as described above, can be obtained using well-known peptide synthesis techniques such as classical solid phase or liquid phase synthesis or synthesized using recombinant DNA technology.
Beneficial technical effects: the invention can improve the stability of bioactive peptides for treating various diseases in vivo, promote the realization of oral administration, improve patient compliance with medication, and reduce side effects, with beneficial economic value.
In order that the invention may be more readily understood and put into practice, one or more preferred embodiments thereof will now be described, only by way of example, with reference to the accompanying drawings.
The various features of the present invention have particularities in the claims. Referring to the following detailed description, a better understanding of the features and advantages of the invention will be obtained, utilizing the principles of the invention in the illustrative embodiment, the figures include:
In order to simplify the structure of natural protease inhibitor SFTI-1, and improve its specificity of active loop and inhibitory activities against serine protease, three series of peptides having intramolecular disulfide bonds were screened and identified using a rational design method. They inhibited the enzymatic activities of trypsin, chymotrypsin, and elastase, respectively, secreted by the pancreas. The activities of these three proteases are the main limiting factor for the absorption of therapeutic peptides and proteins into the blood circulation in the small intestine epithelium. Therefore, four biologically active peptides selected as candidates in the present invention are used to verify whether these three types of peptides with different protease inhibitory activities can be used as a universal molecular scaffold to form a fusion hybrid peptide with therapeutic peptides, whether they can improve the stability of the therapeutic peptides in the hybrid peptide to tolerate metabolic enzyme hydrolysis, and whether they can promote the absorption of the formed hybrid peptide in the intestinal epithelium and the pharmacological activities in vivo. The experimental results confirm that these three types of peptide molecular scaffolds with different protease inhibitory activities can be widely used to improve the stabilities and efficacies of therapeutic peptides and proteins in vivo.
Using the measurement method of inhibiting enzyme activity in vitro, at the first step a truncated monocyclic SFTI-1 mutant BT45 (SEQ ID NO: 45) containing only a disulfide bond was designed and synthesized. The experimental results indicated that its inhibition constant (Ki) was the same as that of monocyclic SFTI-1 (BT1, SEQ ID NO: 1) only containing a disulfide bond (6.4 nM). The results confirmed that the truncated mutant BT45 was the most core peptide (molecular scaffold) for inhibiting trypsin. In order to explore whether the mutation at P3 site will seriously affect the trypsin inhibitory activity of the core scaffold, Cys was mutated to Gly or Ala with the addition of amino acid residues between disulfide bonds, that is, the extended loop between disulfide bonds. The research results confirmed that the molecular scaffold with trypsin inhibitory activity can be changed, then BT2 (SEQ ID NO: 2) and BT3 (SEQ ID NO: 3) were obtained. Besides, in another particular embodiment, the molecular scaffolds including SEQ ID NO: 5, SEQ ID NO: 6, and SEQ ID NO: 7 with enhanced trypsin inhibitory activity was obtained. Combining the truncated core scaffold described above and the extension strategy of the peptide segment between the disulfide bond, a series of amino acid site mutations are performed, and the optimized molecular scaffolds with excellent trypsin inhibitory activities such as SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 16, SEQ ID NO: 17, SEQ ID NO: 25, SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 35, SEQ ID NO: 46, SEQ ID NO: 47, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 51, SEQ ID NO: 53, SEQ ID NO: 54, SEQ ID NO: 55, SEQ ID NO: 57, SEQ ID NO: 60, SEQ ID NO: 65, SEQ ID NO: 66, SEQ ID NO: 67, SEQ ID NO: 69, SEQ ID NO: 70, SEQ ID NO: 71, SEQ ID NO: 74, SEQ ID NO: 75, SEQ ID NO: 76, SEQ ID NO: 77, SEQ ID NO: 78 and SEQ ID NO: 79, were obtained.
The P1 site of a serine protease inhibitory peptide determines the specificity of different serine proteases, along with the P1 sites of chymotrypsin being Tyr and Phe, and the P1 sites of elastase being Ala and Leu. Only a few literatures have reported the molecular scaffolds of active peptide against pancreatic chymotrypsin29,30,31 and elastase32, but their inhibitory activities of them are weak. Based on the core scaffold of anti-trypsin peptide, in the present invention the protease specificity of the molecular scaffold by replacing the P1 site was changed, and then the inhibition activities of peptides with different recognition sites were evaluated. After a series of optimization experiments, the inhibitory scaffold peptides against chymotrypsin were obtained as follows: SEQ ID NO: 85, SEQ ID NO: 90, SEQ ID NO: 91, SEQ ID NO: 98, SEQ ID NO: 105, SEQ ID NO: 106, SEQ ID NO: 113 SEQ ID NO: 114, SEQ ID NO: 115, SEQ ID NO: 131, SEQ ID NO: 132, and SEQ ID NO: 133; and the inhibitory scaffold against porcine pancreatic elastase were obtained as follows: SEQ ID NO: 134, SEQ ID NO: 145, SEQ ID NO: 151, SEQ ID NO: 155, SEQ ID NO: 156, SEQ ID NO: 158, and SEQ ID NO: 162.
Unless otherwise defined herein, all terms used in this application shall have the meanings that are commonly understood by those of ordinary skill in the art. The following definitions provided below were used to illustrate and clarify the description and claims of the present invention.
The singular forms “a”, “an”, and “the” include the plural, unless the context clearly indicates otherwise.
The term “including” is used to mean “including but not limited to”. “Including” and “including but not limited to” are interchangeable.
The term “amino acid” or “any amino acid” as used herein refers to any and all amino acids, including naturally occurring amino acids (e.g α-amino acids), unnatural amino acids, and non-natural amino acids. It includes D-amino acids and L-amino acids. Natural amino acids include those naturally founded in nature, such as, e.g., 20 amino acids that are combined into peptide chains to form structural units of a large number of proteins, and these amino acids are mainly L-stereoisomers. “Unnatural” or “non-natural” amino acids are non-proteinogenic amino acids (i.e., those that are not naturally encoded or do not exist in genetic codons) that are naturally occurring or chemically synthesized.
These “unnatural” or “non-natural” amino acids have the same basic chemical structure as natural amino acids, i.e., compounds that bind to a hydrogen bound carbon, carboxyl, amino, and R-group, such as homocysteine, n-leucine, hydroxyproline, and 2-aminobutyric acid, and retain the same basic chemical structure as natural amino acids when participating in intramolecular peptide bonds.
As is clear to the skilled artisan, the peptide sequence disclosed herein is shown from left to right, wherein the left end of the sequence is the N-terminus of the peptide, and the right end of the sequence being the C-terminal of the peptide.
The terms “protein” and “peptide” are used interchangeably herein and broadly referred to a sequence of two or more amino acids linked together via peptide bonds. It should be understood that the two terms do not imply a specific length of amino acid polymer, nor are they intended to imply or distinguish whether peptides are produced using recombinant techniques, chemical synthesis, or enzymatic synthesis, or whether they are naturally occurring.
The term “a pharmaceutically acceptable salt” as used herein represents the salt or zwitterionic form of the peptide or compound of the present invention, which is water-soluble or oil-soluble or dispersible and suitable for the treatment of diseases without excessive toxicity, irritation, and allergic reactions. They are commensurate with a reasonable benefit/risk ratio and are effective for their intended use. The salt can be prepared during the final separation and purification of the compound, or separately by reacting the amino group with a suitable acid. Representative salts by acid addition reaction include acetate, hydrochloride, lactate, citrate, phosphate, and tartrate.
As used herein, the term “loop” in the present invention refers to the reaction loop, following the nomenclature of Schecter and Berger33. In general formulas (I) and (II), the “loop” has intramolecular disulfide bonds and covers substrate-protease interaction sites. The P1 site corresponding to the Xaa1 residue in General Formulas (I) and (II) is the main determinant of protease specificity.
As used herein, the term “molecular scaffold” refers to and is used interchangeably used with “inhibitory ring”, which has different protease specificity determined by the Xaa1 residue in General Formulas (I) and (II). In some embodiments, the molecular scaffold is a mutant scaffold that contains modifications e.g. substitutions for natural or non-natural amino acids.
The term “linker” used in the present invention broadly refers to a peptide segment rich in glycine or proline that promotes the formation of turn structures, capable of connecting two peptides together and forming a chemical structure.
As is clear to a person skilled in the art, peptides with multiple cysteine residues often form disulfide bonds between two cysteine residues. All such peptides shown in the present invention are defined as optionally comprising one or more of these disulfide bonds.
The term “protease inhibitor” or “enzyme inhibitor” as used in the present invention refers to peptide molecules that inhibit the function of proteases. In one aspect, protease inhibitors (serine protease inhibitors) inhibit protease class from the serine proteases. In another aspect, protease inhibitors inhibit trypsin found in the gastrointestinal tract of mammals.
Glucagon like peptide-1 (GLP-1) is an endogenous hormone with anti-diabetes activity. GLP-1 is inactivated by the exopeptidase dipeptidyl peptidase IV (DPP-IV) and neutral endopeptidase 24.11 (NEP). The half-life of fully active GLP-I in vivo is approximately 90 s. In order to improve its stability in blood circulation, an inhibitory peptide, diprotin A (IPI)34 and/or Opiorphin (QRFSR)35, is connected to the N-terminal of GLP-1 through linkers such as “GG” (two glycine residues). The candidate GLP-1 analogue is further fused with the peptide inhibitor (molecular skeleton) disclosed in the present invention, and its hypoglycemic effect is tested through oral administration. In one embodiment, GLP-1 analogues SEQ ID NO: 184, SEQ ID NOS: 186-209 have been confirmed to have hypoglycemic activity by subcutaneous injection. In another embodiment, SEQ ID NO: 200, SEQ ID NO: 202, SEQ ID NO: 204, and SEQ ID NO: 205 have been confirmed to be absorbed into the blood circulation and have hypoglycemic activity by duodenal administration. The hypoglycemic effect of GLP-1 analogues administered orally can be achieved through enteric coated capsules. In another embodiment, hybrid GLP-1 analogues containing different protease inhibitory peptides are provided with combined effects.
Bacillus subtilisin/type 9 kexin preprotein converting enzyme (PCSK9) regulates low density lipoprotein cholesterol (LDL-C) levels by mediating LDL receptor (LDLR) protein degradation. Since PCSK9 is an important target for controlling plasma LDL-C levels by inhibiting protein protein-protein interaction (PPI) of PCSK9-LDLR, the main strategy for inhibiting PCSK9 binding to LDLR is to effectively reduce LDL-C levels by using LDLR binding sites that antagonize PCSK936. Although these monoclonal antibodies represent successful strategies for suppressing PCSK9, they cannot meet the compliance of patients with long-term treatment. In order to improve patient compliance, the inhibitory peptide Pep2-837 has been identified, but only in vitro biochemical analysis and cell level activity studies have been confirmed. The analogue of Pep2-8 (SEQ ID NO: 210, PCSK9_1) was selected as a candidate therapeutic peptide to further fuse with the peptide serine protease inhibitor (molecular scaffold) disclosed in the present invention, and its therapeutic efficacy in treating hypercholesterolemia was tested by direct duodenal administration. In one embodiment, the inhibition experiment of PCSK9-LDLR molecules confirmed that SEQ ID NO: 211, SEQ ID NO: 212, SEQ ID NO: 214, SEQ ID NO: 215, SEQ ID NO: 216, SEQ ID NO: 217, SEQ ID NO: 218, SEQ ID NO: 224, SEQ ID NO: 225, SEQ ID NO: 226, SEQ ID NO: 227, SEQ ID NO: 228, SEQ ID NO: 229, SEQ ID NO: 230, SEQ ID NO: 231 SEQ ID NO: 232 and SEQ ID NO: 233 have good inhibitory effects in vitro. In another embodiment, a hyperlipidemia model was used to evaluate the effects of subcutaneous injection of SEQ ID NO: 214, SEQ ID NO: 215, SEQ ID NO: 218, SEQ ID NO: 229, SEQ ID NO: 230, and SEQ ID NO: 231. These peptides have excellent lowering lipid (total cholesterol) activities in vivo.
Human calcitonin (hCT) is a peptide hormone that contains 32 amino acid residues and is mainly produced by parafollicular cells of the thyroid gland. Many calcitonin homologues have been isolated, such as salmon calcitonin (sCT), eel calcitonin, porcine calcitonin, and chicken calcitonin. Among them, sCT is more effective and durable than hCT, and has been widely used in the treatment of osteoporosis, bone metastasis, paget disease, hypercalcemia shock, and chronic pain in advanced cancer. Calcitonin is currently only available in solution form and can be administered through intravenous, intramuscular, subcutaneous, or intranasal administration. However, the administration of these calcitonin drugs is significantly less convenient than oral administration, and causes more patient discomfort. Usually, this inconvenience or discomfort can lead to serious non-compliance with the treatment plan. In order to overcome these limitations and provide a better tolerable form of treatment, the sCT analogue is used as a candidate therapeutic peptide, which is further fused with the peptide serine protease inhibitor (molecular scaffold) disclosed in the present invention. Through oral administration, it is confirmed to be effective for treating osteoporosis or osteoarthritis.
Interleukin-17A (IL-17A) is a cytokine secreted by activated Th17 cells, CD8+ T cells, y6 T cells, and NK cells. It can regulate the production of mediators such as antimicrobial peptides (defensins). Various cell types of proinflammatory cytokines and chemokines, such as fibroblasts and synovial cells, are involved in neutrophil biology, inflammation, organ damage, and host defense. IL-17A mediates its action by interacting with interleukin-17 receptor A (IL-17RA) and receptor C (IL-17RC). The inappropriate or excessive production of IL-17A is related to various diseases and relative pathology, including rheumatoid arthritis, airway allergy (including allergic airway diseases such as asthma), skin allergy (including atopic dermatitis), systemic sclerosis, inflammatory bowel diseases including ulcerative colitis and Crohn's disease, and lung diseases including chronic obstructive pulmonary disease. Anti IL-17A's antibodies such as Secukizumab, Ixekizumab, and Bimekizumab have been used to treat IL-17A-mediated inflammatory disorders and diseases. Since the pharmacokinetics, efficacy, and safety of antibody therapy will depend on specific components, there is a need to improve antibody drugs suitable for the treatment of IL-17A mediated diseases. It is difficult to develop small molecule compounds targeting protein interactions due to the large and shallow interaction interfaces of IL-17A/IL-17RA interactions in structure. The fusion of a peptide antagonist with high affinity for IL-17A and anti-IL-22 antibody to form a bispecific fusion body was studied. Unfortunately, these findings reveal the problem of poor stability of inhibitory peptides against IL-17Ain cell cultures38, 39. An analogue of IL-17A peptide antagonist (SEQ ID NO: 238) was selected as a candidate therapeutic peptide and further combined with the peptide inhibitor (molecular scaffold) against serine protease disclosed in the present invention to test the anti-inflammatory activity in vivo through duodenal administration. In one embodiment, the anti-inflammatory activity of SEQ ID NO: 239 and SEQ ID NO: 240 was evaluated by subcutaneous injection using an ear swelling model. In another embodiment, direct duodenal administration was performed, and the results confirmed that SEQ ID NO: 239 and SEQ ID NO: 240 which was absorbed into the blood circulation through the intestinal epithelium had anti-inflammatory activities.
The peptide protease inhibitor obtained in the present invention can be widely used to improve the stability of therapeutic peptides or proteins against digestive enzymes. Among them, therapeutic peptides or proteins are not limited to the peptides disclosed in the present invention and selected as examples. The therapeutic peptide or protein can be selected from the following sequences: LL-37 (SEQ ID NO: 242, LLGDFFRKSKEKEGKEFKRIVQRIKDFLRNLVPRTES) and its analogues with antibacterial, antiviral, and immunomodulatory activities; positively charged cationic antibacterial peptides Histatin 5 (SEQ ID NO: 243, DSHAKRHHGYKRKFHEKHSHSHRGY), indolicin (SEQ ID NO: 244, ILPWKWPWRR), and Pexiganan (SEQ ID NO: 245, GIGKFLKKKKKFGKAFVKILKK) and their analogues; antifungal peptide MAF-1A (SEQ ID NO: 246, KKFKETADKLIESALQQLESSSLAKEMK); anti-HIV Sifuviritide (SEQ ID NO: 247, SWETWEREIENYTRQIYRILEESQEQQDRNERDLLE) and Enfuviritide (SEQ ID NO: 248, YTSLIHSLIEESQNQEQEKNEQELLELDKWASLWWF) and their analogues; anti-HBV peptide Cl-1 (SEQ ID NO: 249, SFYSVLFLWGTCGGFSHSWY) and its analogues; anti-HCV active polypeptides p14 (SEQ ID NO: 250, RRGRTGRGRRGIYR), E2-550 (SEQ ID NO: 251, SWFGCTWMNSTGFTKTC), and C5A (SEQ ID NO: 252, SWLRDIWDWICEVLSDFK) and their analogues; anti-helicobacter pylon active peptides cagL-cagL (SEQ ID NO: 253, KNKNNFIKGIRKLMLAHNK), CagA-ASP2 (SEQ ID NO: 254, GPNIQKLLYQRTTIAAMETI), P1 (SEQ ID NO: 255, TGTLLLILSDVNDNAPIPEPR) and their analogues; DiaPep 277 (SEQ ID NO: 256, VLGGGALLRCIPALDSLTPANEL) and its analogues for treatment of type I diabetes; exendin-4, SEQ ID NO: 257, HGEGTFTSDLSKQMEEEAVRLFIEWLKNGGPSSGAPPPS and its analogues for the treatment of type II diabetes; EGF-A1 (SEQ ID NO: 258, GTNECLDNGGCSHVCNDLKIGYECCPDGFQLVAQRRCEDI), EGF-A5 (SEQ ID NO: 259, GTNECLDNGGCSHVCNDLKIGYECL), and BMS-962476 (SEQ ID NO: 260, PYKHSGYYHRP) and their analogues, which are active peptides for lowering blood lipids; anti-inflammatory active peptides Tag7 (SEQ ID NO: 261, ALRSNYVLKGHRDVQRTLSPG) and ZDC (SEQ ID NO: 262, FNMQQRFYLHPNENAKKSRD) and their analogues; Active peptides that inhibit tumor genesis or development, such as tumor angiogenesis inhibitor endothelin (SEQ ID NO: 263, CPAASARDFQPVLVALCSPLSGGMGRGIR), hypoxia inducible factor 1 α (hypoxia-inducible factor 1 α, HIF-1 α) Inhibitory peptides (SEQ ID NO: 264, GLPQLTSYDCEVNAPIQGSRNLLQGEELLALDQVN), Bcl-2 BH3 (SEQ ID NO: 265, EDIIRNIRHLAQVGDSNDRSIW), human virus entry mediator (HVEM) (SEQ ID NO: 266, ECCPKCSPGYRVKEACGELTGTVCEP), antagonistic peptides such as pDI (SEQ ID NO: 267, LTFEHYWAQLTS) PPKID4 (SEQ ID NO: 268, GPSQPTYPGDDAPVRRLSFFYILLDLYLDAPGVC) and its analogues that antagonize Bak/Bcl-2, and so on. The hybrid peptides formed by these therapeutically active peptides and the peptide protease inhibitors obtained in the present invention may not be limited to subcutaneous injection or oral administration or topical use.
The peptide in the present invention can be prepared by various methods. For example, peptides can be synthesized through commonly used solid-phase synthesis methods, such as α-amino group t-BOC or FMOC protection method well known in the art. Here, amino acids are sequentially added to a growing chain of amino acids. The solid-phase synthesis method is particularly suitable for synthesizing peptides or relatively short peptides in large-scale production, e.g., peptides with a length of up to about 70 amino acids.
The inhibition constants of various synthetic active peptide inhibitors (molecular scaffolds) against seine proteases were measured. The substrates N-succinyl-Ala-Ala-Pro-Phe-p-nitroaniline (AAPFpNA), Nα—Benzoyl-L-arginine-4-nitroaniline hydrochloride (BApNA) and N-succinyl-Ala-Ala-p-nitroaniline (AAApNA) are used in competitive binding reaction to determine the inhibitory activities against α-chymotrypsin, bovine trypsin, and porcine pancreatic elastase, respectively. Experiments for α-chymotrypsin and bovine trypsin inhibition were measured in 20 mM CaCl2, 50 mM Tris-HCl buffer (pH 7.8), and that for porcine elastase inhibition was measured in 50 mM Tris-HCl buffer (pH 8.0). The concentration of the peptide was measured using optical density (OD) at 280 nm. The Michaelis constant (Km) of the enzyme hydrolysis substrate is calculated from the initial rate of substrate hydrolysis at 405 nm. The absorbance value of the substrate was measured at 405 nm after complete hydrolysis. All data were processed using nonlinear regression.
The solid oral pharmaceutical composition in the present invention includes a dosage form, which is an enteric coated capsule. Such capsules are not limited to relatively stable shells used to encapsulate pharmaceutical preparations for oral administration. The two main types of capsules are capsules with hard and soft shells, which are typically used for dry, powdered ingredients, micro pellets, or mini tablets, primarily for oils and active ingredients dissolved or suspended in oils. Both capsules with hard and soft shells can be made from aqueous solutions of gelling agents, e.g., animal proteins, or gelatin, or plant polysaccharides or their derivatives, e.g., carrageenan, and modified forms of starch and cellulose. Other components can be added to the gelling agent solution, such as plasticizers, glycerol, and/or sorbitol, to reduce the hardness of the capsule, colorants, preservatives, disintegrants, lubricants, and surface treatment agents. The capsules in the present invention are coated with polymethacrylic acid/acrylate to form enteric coated capsules. Wherein the capsule packaging material targeting the duodenum and small intestine is selected from Eudragit L100 or L100-55. The packaging material for targeting the colon is selected from Eudragit S100 and can be prepared according to methods well known in the art, e.g., enteric coating or modified enteric coating.
The solid oral pharmaceutical composition in the present invention can be prepared as known in the art. The solid oral pharmaceutical composition can be prepared as described in the embodiments herein.
The example below is provided to illustrate the embodiments in the present invention and is intended only for a better understanding of the present invention, but is not be interpreted as limiting the scope or spirit of the invention.
According to the sequence of the amino acid residues of each polypeptide, the polypeptide is synthesized from C-terminal to N-terminal one by one through the solid-phase chemical synthesis method using Fmoc (9-fluorenylmethoxycarbonyl) amino protective agents; when the synthesis of the linear peptide protected by the side chain of the amino acid is completed, the linear peptide is cut from the resin, the protective group of amino acid residues in the linear peptide is removed, then the intramolecular sulfhydryl group is oxidized to form the disulfide bonds, finally, the target polypeptide is obtained by the purification of HPLC reversed-phase C18 column chromatography.
Fmoc-Asp(OtBu)-Wang resin was selected as the starting material of peptide SEQ ID NO: 1, which was synthesized according to the method described in chemical synthesis of S peptide EQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Arg(Pbf)-Cys(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Pro-Asp(OtBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 1532.31 Da ([M+H]+).
Peptide SEQ ID NO: 10 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Ala-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 1364.72 Da ([M+H]+).
Peptide SEQ ID NO: 211 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2956.82 Da ([M+H]+).
Fmoc-Val-Wang resin was selected as the starting material for chemical synthesis of peptide SEQ ID NO: 212 synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Gly-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 3013.20 Da ([M+H]+).
Fmoc-Ser(tBu)-Wang resin was selected as the starting material for chemical synthesis of peptide SEQ ID NO: 214 synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Gly-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 3012.71 Da ([M+H]+).
Fmoc-Ser(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 215 synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Tyr(tBu)-Leu-Asp(OtBu)-Tyr(tBu)-Val-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Gly-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 3082.43 Da ([M+H]+).
Fmoc-Val-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 216, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Gly-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Tyr(tBu)-Leu-Asp(OtBu)-Trp(Boc)-Val- Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 3105.15 Da ([M+H]+).
Fmoc-Val-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 218, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Gly-Arg(Pbf)-Cys(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Tyr(tBu)-Leu-Asp(OtBu)-Trp(Boc)-Val-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2977.09 Da ([M+H]+).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 224, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Gly-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2999.77 Da ([M+H]+).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 225, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Gly-Ile-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2766.11 Da ([M+H]+).
Fmoc-Val-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 226, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Gly-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2999.12 Da ([M+H]+).
Fmoc-Val-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 227, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ile-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Gly-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2766.78 Da ([M+H]+).
Fmoc-Ser(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 228, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Gly-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Thr(tBu)-Val-Phe-Thr(tBu)- Ser(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2999.34 Da ([M+H]+).
Fmoc-Ser(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 229, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Ala-Leu-Asp(OtBu)-Trp(Boc)-Val-Gly-Ile-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Gly-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2822.72 Da ([M+H]+).
Fmoc-Ser(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 230, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Tyr(tBu)-Leu-Asp(OtBu)-Tyr(tBu)-Val-Gly-Phe-Cys(Trt)-Thr (tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 1021.6 Da ([M−H]3−).
Fmoc-Ser(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 230, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Tyr(tBu)-Leu-Asp(OtBu)-Tyr(tBu)-Val-Gly-Ile-Cys(Trt)-Thr (tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Gly-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2891.97 Da ([M+H]+).
Fmoc-Val-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 232, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Gly-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Tyr(tBu)-Leu-Asp(OtBu)-Trp(Boc)-Val- Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 3091.42 Da ([M+H]+).
Fmoc-Val-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 233, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 9. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Thr(tBu)-Val-Phe-Thr(tBu)-Ser(tBu)-Gly-Ile-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Trp(Boc)-Glu(OtBu)-Glu(OtBu)-Tyr(tBu)-Leu-Asp(OtBu)-Trp(Boc)-Val-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 2858.21 Da ([M+H]+).
Peptide SEQ ID NO: 16 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Leu-Pro-Ala-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1365.09 Da ([M+H]+).
Peptide SEQ ID NO: 17 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Arg(Pbf)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1418.88 Da ([M+2H]2+=710.44).
Peptide SEQ ID NO: 25 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Thr(tBu)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1335.00 Da ([M+2H]2+=668.50).
Peptide SEQ ID NO: 27 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ala-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1374.80 Da ([M+2H]2+=688.40).
Peptide SEQ ID NO: 28 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Nle-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1390.00 Da ([M+2H]2+=696.00).
Peptide SEQ ID NO: 35 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Abu-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1404.50 Da ([M+2H]2+=703.25).
Peptide SEQ ID NO: 46 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Hyp(Trt)-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1446.60 Da ([M+3H]3+=483.20).
Peptide SEQ ID NO: 47 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ser(tBu)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1407.00 Da ([M+3H]3+=470.00).
Peptide SEQ ID NO: 49 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ile-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1432.50 Da ([M+3H]3+=478.50).
Peptide SEQ ID NO: 50 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Nle-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1432.50 Da ([M+3H]3+=478.50).
Peptide SEQ ID NO: 51 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Val-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1418.40 Da ([M+3H]3+=473.80).
Peptide SEQ ID NO: 53 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Tyr(tBu)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1482.90 Da ([M+3H]3+=495.30).
Peptide SEQ ID NO: 54 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Gln(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1447.50 Da ([M+3H]3+=483.50).
Peptide SEQ ID NO: 55 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Asn(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1433.40 Da ([M+3H]3+=478.80).
Peptide SEQ ID NO: 57 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Trp(Boc)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1505.70 Da ([M+3H]3+=502.90).
Peptide SEQ ID NO: 60 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Gly-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1376.20 Da ([M+2H]2+=689.10).
Fmoc-Ser(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 65, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Arg(Pbf)-Cys(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Leu-Pro-Pro-Gln(Trt)-Cys(Trt)-Ser(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1216.80 Da ([M+3H]3+=406.60).
Peptide SEQ ID NO: 66 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Pro-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1430.10 Da ([M+3H]3+=477.70).
Peptide SEQ ID NO: 67 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Ala-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1404.30 Da ([M+3H]3+=469.10).
Peptide SEQ ID NO: 69 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Ala-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Hyp(Trt)-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1420.80 Da ([M+3H]3+=474.60).
Peptide SEQ ID NO: 70 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Ala-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Hyp(Trt)-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1420.80 Da ([M+3H]3+=474.60).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 85, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr (tBu)-Phe-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1360.02 Da ([M+K+H]2+=700.01).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 90, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1375.55 Da ([M+Na]=1398.55).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 91, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ser(tBu)-Cys(Trt)-Thr(tBu)-Phe-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1300.55 Da ([M+H]+).
Peptide SEQ ID NO: 98 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ala-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Ala-Lys(Boc)-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1200.80 Da ([M+2H]2+=601.40).
Fmoc-Asn(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 105, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Thr(tBu)-Cys(Trt)-Thr(tBu)-Phe-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Asn(Trt)-Pro-Asn(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1461.00 Da ([M+2H]=731.50).
Fmoc-Asn(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 106, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Thr(tBu)-Cys(Trt)-Thr(tBu)-Phe-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Asn(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1249.50 Da ([M+Na]m=1272.50).
Fmoc-Tyr(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 113, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1318.80 Da ([M+2H]2+=660.40).
Fmoc-Ala-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 114, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1390.80 Da ([M+2H]2+=696.40).
Fmoc-Arg(Pbf)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 115, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Arg(Pbf)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1312.20 Da ([M+2H]2+=657.10).
Fmoc-Tyr(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 131, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Pro-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1268.80 Da ([M+2H]2+=635.40).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 132, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Hyp(Trt)-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1392.40 Da ([M+2H]2+=697.20).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 133, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Hyp(Trt)-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1392.00 Da ([M+2H]2+=697.00).
Fmoc-Tyr(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 134, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Leu-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1193.20 Da ([M+2H]2=597.60).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 145, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Leu-Cys(Trt)-Thr (tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1143.50 Da ([M+H]+).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 151, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Leu-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1157.6 Da ([M+2H]2=579.80).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 155, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Leu-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1129.10 Da ([M+2H]2+=565.55).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 156, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ile-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1143.15 Da ([M+H]+).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 158, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Leu-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Asn(Trt)-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1143.80 Da ([M+2H]2+=572.90).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 162, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Tyr(tBu)-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1193.30 Da ([M−H]−=1192.30).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 163, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Ala-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1270.80 Da ([M+2H]2+=636.40).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 164, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Abu-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1285.70 Da ([M+H]=1285.70).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 165, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Nle-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1312.80 Da ([M+2H]2+=657.40).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 166, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Leu-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1313.00 Da ([M+2H]2+=657.50).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 167, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Ser(tBu)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1287.00 Da ([M+2H]2=644.50).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 168, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Thr(tBu)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1301.95 Da ([M+H]+).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 169, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Phe-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1346.80 Da ([M+2H]2+=674.40).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 170, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Tyr(tBu)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1363.23 Da ([M+H]+).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 171, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Asn(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1314.27 Da ([M+H]+).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 172, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Gln(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1327.80 Da ([M+2H]2+=664.90).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 173, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-His(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1337.00 Da ([M+2H]2+=669.50).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 174, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Arg(Pbf)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1356.58 Da ([M+H]+).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 175, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Lys(Boc)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1328.00 Da ([M+2H]2+=665.00).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 176, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Ile-Trp(Boc)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1386.33 Da ([M+H]+).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 177, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Pro-Ile-Ala-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1311.70 Da ([M+H]=1311.70).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 178, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Ala-Ile-Ala-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1285.40 Da ([M+2H]2+=643.70).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 179, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Hyp(Trt)-Ile-Ala-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1327.20 Da ([M+2H]2+=664.60).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 180, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ile-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Hyp(Trt)-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1159.20 Da ([M+2H]2+=580.60).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 181, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ile-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Hyp(Trt)-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 1158.60 Da ([M−H]−=1157.60).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 194, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Arg(Pbf)-Cys(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Pro-Gly-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)- Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5492.00 Da ([M+8H]8+=687.50).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 195, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Arg(Pbf)-Cys(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Pro-Gly-Gly-Gln (Trt)-Arg(Pbf)-Phe-Ser(tBu)-Arg(Pbf)-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val- Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5842.40 Da ([M+8H]8+=731.30).
Fmoc-Pro-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 196, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala- Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Arg(Pbf)-Cys(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Pro-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5437.75 Da ([M+5H]5+=1088.55).
Fmoc-Pro-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 197, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Gln(Trt)-Arg(Pbf)-Phe-Ser(tBu)-Arg(Pbf)-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala- Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Arg(Pbf)-Cys(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Pro-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5789.70 Da ([M+6H]6+=965.95).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 198, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Gly-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)- Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5465.85 Da ([M+5H]5+=1094.17).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 199, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Gly-Gly-Gln(Trt)-Arg(Pbf)-Phe-Ser(tBu)-Arg(Pbf)-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe- Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5815.56 Da ([M+6H]6+=970.26).
Fmoc-Phe-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 200, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala- Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5465.60 Da ([M+7H]8+=781.80).
Fmoc-Phe-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 201, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Gln(Trt)-Arg(Pbf)-Phe-Ser(tBu)-Arg(Pbf)-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala- Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5816.70 Da ([M+6H]6+=970.45).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 202, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ser(tBu)-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)- Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5333.10 Da ([M−3H]3−=1776.70).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 203, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala- Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Ser(tBu)-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5391.00 Da ([M+5H]5+=1079.20).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 204, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val- Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5395.20 Da ([M−3H]3−=1797.40).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 205, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala- Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5450.50 Da ([M+5H]5+=1091.10).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 206, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Leu-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val- Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5268.50 Da ([M+5H]5+=1054.70).
Fmoc-Tyr(tBu)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 207, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe- Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Leu-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5267.00 Da ([M+5H]5+=1054.40).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 208, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Leu-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Gly-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)- Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5218.00 Da ([M+5H]5+=1044.60).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 209, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe- Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Leu-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 5218.00 Da ([M+5H]5+=1044.60).
Fmoc-Phe-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 239, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ile-His(Trt)-Val-Thr(tBu)-Ile-Pro-Ala-Asp(OtBu)-Leu-Trp(Boc)-Asp(OtBu)-Trp(Boc)-Ile-Asn(Trt)-Gly-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 3122.40 Da ([M+4H]4+=781.60).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 240, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ile-His(Trt)-Val-Thr(tBu)-Ile-Pro-Ala-Asp(OtBu)-Leu-Trp(Boc)-Asp(OtBu)-Trp(Boc)-Ile-Asn(Trt)-Gly-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 3108.00 Da ([M+3H]3+=1037.00).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 240, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 45. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Ile-His(Trt)-Val-Thr(tBu)-Ile-Pro-Ala-Asp(OtBu)-Leu-Trp(Boc)-Asp(OtBu)-Trp(Boc)-Ile-Asn(Trt)-Gly-Ile-Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained by separation and purification with the measured molecular weight of 2874.90 Da ([M+3H]3+=959.30).
Peptide SEQ ID NO: 33 was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 29. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-homoCys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Ala-Phe-Gly-homoCys(Trt)-2-Cl-Trt resin. Then the Fmoc group was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 1546.60 Da ([[M+2H]2+=774.30).
Fmoc-Gly-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 236, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 235. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Acm)-Ser(tBu)-Asn(Trt)-Leu-Ser(tBu)-Thr(tBu)-Cys(Acm)-Gly-Leu-Gly-Lys(Boc)-Leu-Ser(tBu)-Gln(Trt)-Glu-Ala-His(Trt)-Lys(Boc)-Leu-Gln(Trt)-Thr(tBu)-Tyr(tBu)-Pro-Arg(Pbf)-Thr(tBu)-Asn (Trt)-Thr(tBu)-Gly-Ser(tBu)-Gly-Thr(tBu)-Pro-Arg(Pbf)-Thr(tBu)-Asn(Trt)-Thr(tBu)-Gly-Ser(tBu)-Gly-Thr(tBu)-Pro-Gly-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 4764.50 Da ([M+5H]5+=953.90).
Fmoc-Gln(Trt)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 237, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 235. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-Cys(Acm)-Ser(tBu)-Asn(Trt)-Leu-Ser(tBu)-Thr(tBu)-Cys(Acm)-Gly-Leu-Gly-Lys(Boc)-Leu-Ser (tBu)-Gln(Trt)-Glu(OtBu)-Ala-His(Trt)-Lys(Boc)-Leu-Gln(Trt)-Thr(tBu)-Tyr(tBu)-Pro-Arg(Pbf)-Thr(tBu)-Asn(Trt)-Thr(tBu)-Gly-Ser(tBu)-Gly-Thr(tBu)-Pro-Arg(Pbf)-Thr(tBu)-Asn(Trt)-Thr(tBu)-Gly-Ser(tBu)-Gly-Thr(tBu)-Pro-Gly-Ile- Cys(Trt)-Thr(tBu)-Ala-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Gln(Trt)-Wang resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of cleavage buffer, followed by formation of disulfide bond via oxidation. Finally, the target peptide segment was obtained with the measured molecular weight of 4531.50 Da ([M+5H]5+=907.30).
Fmoc-Pro-Rink Amide-AM resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 196, which was synthesized according to the method described in SEQ ID NO: 194. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Ac-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val- Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Arg(Pbf)-Cys(Trt)-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Pro-Rink Amide-AM resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of cleavage buffer, followed by formation of disulfide bond via oxidation. Finally, the target peptide segment is obtained with the measured molecular weight of 5476.14 Da ([M+H]+).
Fmoc-Lys(Boc)-Rink Amide-AM resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 198, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 194. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Ac-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Gly-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)- Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Rink Amide AM resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment is obtained with the measured molecular weight of 5506.83 Da ([M+H]+).
Fmoc-Phe-Rink Amide-AM resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 198, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 194. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Ac-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)-Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe- Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Gly-Cys(Trt)-Gly-Arg(Pbf)-Ala-Thr(tBu)-Lys(Boc)-Ser(tBu)-Ile-Pro-Pro-Ile-Cys(Trt)-Phe-Rink Amide AM resin. Then the Fmoc was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment is obtained with the measured molecular weight of 5507.42 Da ([M+H]+).
Fmoc-Lys(Boc)-Wang resin was selected as the starting material of chemical synthesis of peptide SEQ ID NO: 204, which was synthesized according to the method described in chemical synthesis of peptide SEQ ID NO: 200. At first, the amino acids were added successively to synthesize the peptide segment with the protecting groups, namely Fmoc-PEG-Phe-Cys(Trt)-Thr(tBu)-Tyr(tBu)-Ser(tBu)-Ile-Pro-Pro-Gln(Trt)-Cys(Trt)-Tyr(tBu)-Gly-Gly-Ile-Pro-Ile-Gly-Gly-His(Trt)-Ala-Glu(OtBu)-Gly-Thr(tBu)-Phe-Thr(tBu)-Ser(tBu)-Asp(OtBu)- Val-Ser(tBu)-Ser(tBu)-Tyr(tBu)-Leu-Glu(OtBu)-Gly-Gln(Trt)-Ala-Ala-Lys(Boc)-Glu(OtBu)-Phe-Ile-Ala-Trp(Boc)-Leu-Val-Lys(Boc)-Gly-Arg(Pbf)-Gly-Gly-Lys(Boc)-Wang resin. Then the Fmoc group was removed, and the resin and the side-chain protecting groups were also removed by addition of the cleavage buffer, followed by formation of the disulfide bond via oxidation. Finally, the target peptide segment is obtained, the chemical structure is Characterized by Mass Spectrometry, the Measured Molecular Weight is 5817.47 Da ([M+H]+).
Residual activity of the enzyme (%)=(1−(Max OD405 nm−Sample OD405 nm)/(Max OD405 nm−Min OD405 nm))*100
Plotted the residual activity of the enzyme with substrate concentration to obtain the half inhibitory concentration (IC50) of BTs scaffold against trypsin. Then, substituted it into the formula Ki=IC50/(1+S/Km) (S, IC50 and Km were substrate concentration, half inhibitory concentration and Michaelis constant, respectively) to obtain the inhibition constant Ki of BTs scaffold against trypsin.
According to the OD405 nm value of pNA produced by trypsin hydrolyzing different concentrations of BApNA in reference to that of the standard curve, plotted the initial velocity V0 with the concentration of substrate BApNA using Prism software, obtaining Michaelis constant Km value of 0.33 mM (R2=0.9966) (
Mutation studies at the sites P2 (BT26), P3 (BT35), P4 (BT25), and P5 (BT66) of BT9 have been found that it could be replaced by other amino acid residues, with alanine substitution of the P3 site being replaced by γ-aminobutyric acid exhibited almost equivalent inhibitory activity of peptide BT9 against trypsin, leading to the further synthesis of a series of BT47-BT60 scaffolds targeting the P3 site. Among them, mutants BT47, BT50, BT53, and BT54 exhibited good inhibitory activities against trypsin (
a: A disulfide bond is formed between two cysteine residues of anti-trypsin peptide
24.1± 0.5
Residual activity of enzyme (%)=(1−(Max OD405 nm−Sample OD405 nm)/(Max OD405 nm−Min OD405 nm))*100
Plotted the residual activity of enzyme with substrate concentration to obtain the half inhibitory concentration (IC50) of anti-chymorypsin peptides (CHs). Then, substituted it into the formula Ki=IC50/(1+S/Km) (S, IC50, and Km were substrate concentration, half inhibitory concentration, and Michaelis constant, respectively) to obtain the inhibition constant Ki of anti-chymorypsin peptides (CHs).
Using a certain concentration of chymotrypsin to catalyze different concentrations of AAPFpNA to produce pNA, and the absorbance value of OD405 nm was measured. Referring to the standard curve, Prism software was used to plot the initial velocity V0 with the concentration of substrate AAPFpNA, and the Michaelis constant Km value of chymotrypsin hydrolyzing AAPFpNA was obtained to be 0.38 mM (R2=0.9988) (
There is limited research on active peptides derived from BBI and SFTI-1 that inhibit chymotrypsin. A literature had reported that peptide analog CH4 derived from SFTI-1 has good inhibitory activity against chymotrypsin [McBride J D, Freeman N, Domingo G J, Leatherbarrow R J. Selection of chymotrypsin inhibitors from a conformationally constrained combinatorial peptide library. J Mol Biol, 1996, 259: 819-827]. The invention combined the specificity of serine protease at P1 site and the results of anti-trypsin peptides to synthesize peptides CH1, CH4, and CH5 with 0.46, 0.55, and 0.08 μM of inhibition constants Ki against chymotrypsin. At the same time, similar peptides CH2, CH3, CH6, CH7, CH8, and CH9 were synthesized based on the characteristics of the ring extension between the disulfide bonds of anti-trypsin peptides. Only CH7 and CH9 had certain inhibitory activity against chymotrypsin, indicating that chymotrypsin may differ structurally from trypsin, and the ring extension structure between disulfide bonds is not suitable for optimizing the structure of anti-chymotrypsin peptides (
Based on the specificity of chymotrypsin P1 site and the good inhibitory activity of peptide CH5, a series of analogues and ring-expanding analogues of their disulfide bond loop were synthesized for the substitutions of P1 and P4 sites of amino acid residues. Then the chymotrypsin inhibition constant was determined, and the results showed that peptide CH10 had good inhibitory activity (Ki=30 nM). Compared with the inhibitory activity of CH11, CH17, CH18, and CH19, the P1 site was preferably tyrosine, while the P4 site was preferably hydrophobic amino acid residue; The corresponding analogues CH13, CH23, and CH24 of disulfide bond ring expanding also exhibit good inhibitory activity (
a: A disulfide bond is formed between two cysteine residues within the peptide
Residual activity of enzyme (%)=(1−(Max OD405 nm−Sample OD405 nm)/(Max OD405 nm−Min OD405 nm))*100
Plot the residual activity of enzyme with substrate concentration to obtain the half inhibitory concentration (IC50) of peptide scaffolds ECs against elastase. Then, substitute it into the formula Ki=IC50/(1+S/Km) (S, IC50, and Km are substrate concentration, half inhibitory concentration, and Michaelis constant, respectively) to obtain the inhibition constant Ki of ECs skeleton inhibiting elastase.
Using a certain concentration of elastase to catalyze different concentrations of AAApNA to produce pNA, and the absorbance value of OD405 nm was measured. Referring to the standard curve, Prism software was used to plot the initial velocity V0 with the concentration of substrate AAApNA, and the Michaelis constant Km value of elastase hydrolyzing AAApNA was obtained to be 0.40 mM (R2=0.9885) (
There are few reports on the active peptides of pancreatic elastase, and only the literature reports that the analogues of peptide EC1 have good inhibitory activity against pancreatic elastase [McBride J D, Free H N, Leatherbarrow R J. Selection of human elastase inhibitors from a conformably constrained combinatorial peptide library. Eur J Biochem, 1999, 266: 403-412.]. In this invention, the elastase inhibitory peptides EC1-EC12 based on the specificity of serine protease with P1 site and the results of trypsin and chymotrypsin inhibitory peptides had been synthesized. The results of determining the inhibition constant Ki of Elastase showed that peptides EC1 and EC12 with alanine at P1 site had better inhibitory activity against Elastase, and EC12 had better inhibitory activity than peptides EC1 and EC2, indicating that amino acid substitution at P5′ and P7′ sites had a great impact on its inhibitory activity, while only the analog EC7 with disulfide ring extension, showed weaker inhibitory activity (
a: A disulfide bond is formed between two cysteine residues within the peptide
To improve the stability of GLP-1 in blood circulation, GLP-1 analogues (hybrid peptides), which contain DPP-IV inhibitory peptide diprotin A (IPI) and NEP24.11 inhibitory peptide Opiorphin (QRFSR) were designed and synthesized. The structural sequences are shown in Table 13.
To investigate the tolerance of GLP-1 and its analogues to DPP-IV, the following experiments were carried out:
Control test: Take three sterile EP tubes and add 5 μL of 250 μM GLP-1 or GLP-1 analogs, 45 μL of 100 mM Tris-HCl buffer (pH 8.0) and 7.5 μL of 10% TFA. Mix by centrifugation at 8000 rpm for 30 seconds.
Enzymatic hydrolysis kinetics of DPP-IV on GLP-1 and its analogues (hybrid peptides): (1) Take three sterile EP tubes and separately add 30 μL of 250 μM GLP-1 or GLP-1 analogs and 240 μL of 100 mM Tris-HCl buffer (pH 8.0). (2) Arrange a certain volume of 0.005 μg/μL DPP-IV solution in another sterile EP. (3) Incubate the EP tubes containing peptides and enzymes at 37° C. for 5 min, and separately add 30 μL of DPP-IV solution to each EP tube containing peptides and mix well. Start timing and remove 50 μL of reaction solution at 0.5, 2.0, 4.0, 8.0, and 12.0 hours later, respectively. Then add 7.5 μL of 10% TFA to terminate the reaction and mix well by centrifugation at 8000 rpm for 30 seconds. In the 50 μL of reaction system, the final concentrations of GLP-1 or GLP-1 analogues and DPP-IV were 25 μM and 0.5 ng/μL, respectively. There were three replicates at each time point, and the peak area of the peptide at each time point was detected using reverse phase high-performance liquid chromatography (RP-HPLC). The ratio of the remaining peak area of the sample at detection time T (h) to the peak area of the prototype peptide at 0 h was calculated as the remaining percentage (%) of the peptide.
Results: To rule out the influence of trypsin inhibitory peptides on the hydrolysis of GLP-1 and its analogues by DPP-IV, GLP-1 analogues SEQ ID NO: 189, SEQ ID NO: 190, SEQ ID NO: 191, and SEQ ID NO: 193 containing partial peptide segment of BT43 (SEQ ID NO: 43) were synthesized (Table 13). Determine the remaining prototype sample ratio of experimental samples after DPP-IV treatment for different time by HPLC. The results showed that seven glycine residues directly attached at the N-terminus of GLP-1 (G7-GLP-1, SEQ ID NO: 186) can form a protective effect on the tolerance of GLP-1 to DPP-IV degradation. After 12 hours of treatment, G7-GLP-1 still had about 34.5% remaining, while GLP-1 (7-37) had been absolutely degraded after about 4 hours; Introduction of DPP-IV inhibitory peptide diprotin A (IPI) in D-GLP-1 (SEQ ID NO: 187) showed good stability in tolerating DPP-IV degradation, and 85.6% of prototype peptide remained after 12 hours of treatment (
SCTYSIPPQCYGGIPIGGHAEGTFTSDVSSYLEGQ
FCTYSIPPQCYGGIPIGGHAEGTFTSDVSSYLEGQ
LCTASIPPQCYGGIPIGGHAEGTFTSDVSSYLEGQ
LCTASIPPICQGGIPIGGHAEGTFTSDVSSYLEGQ
aThe peptide scaffolds against DPP-IV, NEP24.11, trypsin, chymotrypsin and elastase are separately named D, N, T, BT, CH and EC, and are marked with straight lines, wavy lines, dotted lines, double straight lines and italics. In addition, disulfide bonds are formed between the two cysteine residues in the peptide scaffolds against trypsin, chymotrypsin and elastase in the polypeptide sequence.
Control test: Take three sterile EP tubes and add 6 μL of 250 μM GLP-1 or GLP-1 analogs, and 44 μL of reaction buffer (50 mM HEPES, pH 7.4, 50 mM NaCl), and 7.5 μL of 10% TFA. Mix by centrifugation at 8000 rpm for 30 seconds.
Enzymatic hydrolysis kinetics of NEP24.11 on GLP-1 and its analogues (hybrid peptides): Take three sterile EP tubes and separately add 30 μL of 250 μM GLP-1 or GLP-1 analogs, and 215 μL of reaction buffer (50 mM HEPES, pH 7.4, 50 mM NaCl). Arrange a certain volume of 0.04 μg/μL NEP24.11 enzyme solution in another sterile EP. Incubate the EP tubes containing peptides and enzymes at 37° C. for 5 min, and add 5 μL of NEP24.11 solution to each EP tube containing peptides and mix well. Start timing and remove 50 μL of reaction solution at 0.5, 2.0, 4.0, and 8.0 hours later, respectively. Add 7.5 μL of 10% TFA to terminate the reaction and mix well by centrifugation at 8000 rpm for 30 seconds. In the 50 μL of reaction system, the final concentrations of GLP-1 or GLP-1 analogues and NEP24.11 were 30 μM and 1.0 ng/μL, respectively. There are three replicates at each time point, and the peak area of the peptide at each time point is detected using reverse phase high-performance liquid chromatography (RP-HPLC). The ratio of the remaining peak area of the sample at detection time T (h) to the peak area of the prototype peptide at 0 h is calculated as the remaining percentage (%) of the peptide.
Results: After 8 hours of enzymatic hydrolysis by NEP24.11, GLP-1 (7-37) and G7-GLP-1 were almost completely degraded. The stability of N-GLP-1 (SEQ ID NO: 188) containing the peptide segment of Opiorphin (QRFSR) that inhibits NEP24.11, has been improved the most, with a remaining amount of about 56.4%, indicating that this Opiorphin (QRFSR) peptide segment can indeed exert an inhibitory effect on NEP24.11. Due to the scattered distribution of the cleavage sites of NEP24.11 throughout the GLP-1 molecule, molecules containing two or three inhibitory peptide scaffolds may have varying degrees of tolerance to NEP24.11 due to steric hindrance. The most stable D-GLP-1-BT1 (SEQ ID NO: 196) has a residual amount of nearly 80% after 8 hours of enzyme interaction (Table 15). The kinetic process of NEP24.11 enzymatic hydrolysis of GLP-1 and its analogues is shown in
Control test: Take three sterile EP tubes and add 1.5 μL of 1 mM GLP-1 or GLP-1 analogs, 23.5 μL of reaction buffer (20 mM CaCl2, pH 7.8, 50 mM Tris-HCl), and 3.75 μL of 10% TFA. Mix by centrifugation at 8000 rpm for 30 seconds.
Enzymatic hydrolysis kinetics of trypsin on GLP-1 analogues (SEQ ID NO: 186-193) without peptide scaffolds against trypsin: Take three sterile EP tubes and add 9 μL of 1 mM GLP-1 or GLP-1 analogs, and 135 μL of reaction buffer (20 mM CaCl2, pH 7.8, 50 mM Tris-HCl). Arrange a certain volume of 0.05 μg/μL trypsin solution in another sterile EP. Incubate the EP tubes containing peptides and enzymes at 37° C. for 5 min, and separately add 6 μL of trypsin solution to each EP tube containing peptides and mix well. Start timing and extract 25 μL of reaction solution at 1.5, 3.0, 4.5, 6.0 and 9.0 min later, respectively. Add 3.75 μL of 10% TFA to terminate the reaction and mix well by centrifugation at 8000 rpm for 30 seconds.
Enzymatic hydrolysis kinetics of trypsin on GLP-1 analogues (SEQ ID NO: 194-201) containing peptide scaffolds against trypsin: Take three sterile EP tubes and add 13.5 μL of 1 mM GLP-1 or GLP-1 analogs and 202.5 μL of reaction buffer (20 mM CaCl2, pH 7.8, 50 mM Tris-HCl). Arrange a certain volume of 0.05 μg/μL trypsin solution in another sterile EP. Incubate the EP tubes containing peptides and enzymes at 37° C. for 5 min, and add 9 μL of trypsin solution to each EP tube containing peptides and mix well. Start timing and extract 25 μL of reaction solution at 1.5, 3.0, 4.5, 6.0, 9.0, 15.0, 30.0, and 60.0 min later, respectively. Add 3.75 μL of 10% TFA to terminate the reaction and mix well by centrifugation at 8000 rpm for 30 seconds.
In the 25 μL of reaction system of two different sets described above, the final concentrations of GLP-1 or GLP-1 analogues and trypsin were 60 μM and 2.0 ng/μL, respectively. There are three replicates at each time point, and the peak area of the peptide at each time point is detected using reverse phase high-performance liquid chromatography (RP-HPLC). The ratio of the remaining peak area of the sample at detection time T (h) to the peak area of the prototype peptide at 0 h is calculated as the remaining percentage (%) of the peptide.
Results: GLP-1 analogs SEQ ID NO: 186-193, which does not contain the inhibitory peptide scaffols against trypsin, has poor tolerance to trypsin hydrolysis and is almost degraded at 9 min; Although the trypsin inhibitory activity of BT43 (SEQ ID NO: 43) is weak, GLP-1 analogues containing a partial inhibitory peptide segment of BT43 (SEQ ID NO: 43) exhibited certain tolerance (
Control test: Take three sterile EP tubes and add 1.5 μL of 1 mM GLP-1 or GLP-1 analogs, 23.5 μL of reaction buffer (20 mM CaCl2, pH 7.8, 50 mM Tris-HCl), and 3.75 μL of 10% TFA. Mix by centrifugation at 8000 rpm for 30 seconds.
Enzymatic hydrolysis kinetics of chymotrypsin on GLP-1 analogues (SEQ ID NO: 186-201) without inhibitory peptide scaffolds against chymotrypsin: Take three sterile EP tubes and add 9 μL of 1 mM GLP-1 or GLP-1 analogs and 138 μL of reaction buffer (20 mM CaCl2, pH 7.8, 50 mM Tris-HCl). Arrange a certain volume of 0.05 μg/μL chymotrypsin solution in another sterile EP. Incubate the EP tubes containing peptides and enzymes at 37° C. for 5 min, and add 3 μL of trypsin solution to each EP tube containing peptides and mix well. Start timing and extract 25 μL of reaction solution at 1.5, 3.0, 4.5, 6.0 and 9.0 min later, respectively. Add 3.75 μL of 10% TFA to terminate the reaction and mix well by centrifugation at 8000 rpm for 30 seconds.
Enzymatic hydrolysis kinetics of chymotrypsin on GLP-1 analogues (SEQ ID NO: 202-205) containing inhibitory peptide scaffolds against chymotrypsin: Take three sterile EP tubes, and add 13.5 μL of 1 mM GLP-1 or GLP-1 analogs and 207 μL of reaction buffer (20 mM CaCl2, pH 7.8, 50 mM Tris-HCl). Arrange a certain volume of 0.05 μg/μL chymotrypsin solution in another sterile EP. Incubate the EP tubes containing peptides and enzymes at 37° C. for 5 min, and then add 4.5 μL of chymotrypsin solution to each EP tube containing peptides and mix well. Start timing and extract 25 μL of reaction solution at 1.5, 3.0, 4.5, 6.0, 9.0, 15.0, 30.0, and 60.0 min later, respectively. Add 3.75 μL of 10% TFA to terminate the reaction and mix well by centrifugation at 8000 rpm for 30 seconds.
In the 25 μL of reaction system of two different sets described above, the final concentrations of GLP-1 or GLP-1 analogues and chymotrypsin were 60 μM and 1.0 ng/μL, respectively. There are three replicates at each time point, and the peak area of the peptide at each time point is detected using reverse phase high-performance liquid chromatography (RP-HPLC). The ratio of the remaining peak area of the sample at detection time T (h) to the peak area of the prototype peptide at 0 h is calculated as the remaining percentage (%) of the peptide.
Results: After 9 min of chymotrypsin hydrolysis, GLP-1 was completely degraded, and the results of two experiments were consistent. GLP-1 analogues SEQ ID NO: 186-201 do not contain inhibitory peptide scaffolds against chymotrypsin, and their stability towards chymotrypsin hydrolysis is relatively low. However, GLP-1 analogues SEQ ID NO: 189-191 and SEQ ID NO: 193, which contain a partial inhibitory peptide segment of BT43 (SEQ ID NO: 43), exhibited certain tolerance compared to GLP-1 molecules, with more than 50% of the remaining prototype peptides after 9 min of chymotrypsin hydrolysis (
Control test: Take three sterile EP tubes and add 1.5 μL of 1 mM GLP-1 or GLP-1 analogs, 23.5 μL of reaction buffer (50 mM Tris-HCl, pH 8.0), and 3.75 μL of 10% TFA. Mix by centrifugation at 8000 rpm for 30 seconds.
Enzymatic hydrolysis kinetics of elastase on GLP-1 analogues (SEQ ID NO: 206-209) containing inhibitory peptide scaffolds against elastase: Take three sterile EP tubes, and add 13.5 μL of 1 mM GLP-1 or GLP-1 analogs and 207 μL of reaction buffer (50 mM Tris-HCl, pH 8.0). Arrange a certain volume of 0.5 μg/μL elastase solution in another sterile EP. Incubate the EP tubes containing peptides and enzymes at 37° C. for 5 min, and then add 4.5 μL of elastase solution to each EP tube containing peptides and mix well. Start timing and remove 25 μL of reaction solution at 1.5, 3.0, 4.5, 6.0, 9.0, 15.0, 30.0, and 60.0 min later, respectively. Add 3.75 μL of 10% TFA to terminate the reaction and mix well by centrifugation at 8000 rpm for 30 seconds. In the 25 μL of reaction system, the final concentrations of GLP-1 or GLP-1 analogues and elastase were 60 μM and 10 ng/μL, respectively. There are three replicates at each time point, and the peak area of the peptide at each time point is detected using reverse phase high-performance liquid chromatography (RP-HPLC). The ratio of the remaining peak area of the sample at detection time T (h) to the peak area of the prototype peptide at 0 h is calculated as the remaining percentage (%) of the peptide.
Results: Based on the fact that GLP-1 analogs containing the inhibitory peptide scaffolds against trypsin and chymotrypsin have the tolerance to hydrolysis of metabolic enzymes, in this experimental only the tolerance of GLP-1 analogs containing elastase inhibitory peptides (SEQ ID Nos: 206-209) to degradation of elastase were evaluated. The results showed that about 10% of GLP-1 was left after 15 min of enzymatic hydrolysis, and the remaining of GLP-1 analogues containing inhibitory peptides against elastase was more than 50%. After 30 minutes of enzymatic hydrolysis, no GLP-1 prototype molecule was detected. After 60 min of enzymatic hydrolysis, about 20% of GLP-1 analogs (SEQ ID NO: 206, SEQ ID NO: 208) fused with inhibitory peptide against elastase at the N-terminus remained; However, about 45% of GLP-1 analogs (SEQ ID NO: 207, SEQ ID NO: 209) fused with inhibitory peptide against elastase at the C-terminus remained, indicating that the introduction of EC inhibitory peptide molecules into the C-terminal of GLP-1 molecule can better improve its stability of enzymatic hydrolysis of elastase (
Control test: Take three sterile EP tubes and sequentially add 3 μL of 1 mM GLP-1 or GLP-1 analogs, 25 μL of human serum (obtained from SenBeiJia Biological Technology Co., Ltd.), 72 μL of reaction buffer (50 mM Tris-HCl, pH7.0), and 300 μL of pre-cold absolute methanol. Invert and mix thoroughly, then leave at −20° C. overnight. At the same time, take three sterile EP tubes and add 25 μL of human serum, 75 μL of 50 mM Tris-HCl buffer (pH7.0), and 300 μL of pre-cold absolute methanol. Invert and mix thoroughly, then leave at −20° C. overnight as a negative control, so as to eliminate the interference of proteins or peptides contained in human serum at the peak time of the target peptide after methanol precipitation.
Serum stability experiment: Take three sterile EP tubes and sequentially add 16.5 μL of 1 mM GLP-1 or GLP-1 analogs, and 396 μL of reaction buffer (50 mM Tris-HCl, pH 8.0). Arrange a certain volume of human serum in another sterile EP. Incubate the EP tubes containing peptides and serum at 37° C. for 10 min, and add 137.5 μL of human serum to each EP tube containing peptides and mix well. The final concentrations of GLP-1 or GLP-1 analogues and human serum were 0.03 mM and 25% (v/v), respectively. Start timing and remove 100 μL of reaction solution at 0.5, 2.0, 4.0, 8.0, and 12.0 h later, respectively. Add 300 μL of pre-cold absolute methanol. Invert and mix thoroughly, then leave at −20° C. overnight. All samples were centrifuged at 4° C. for 10 min at 18000 g, and the supernatant was taken and subjected to drain organic solvent using a suction bottle and freeze-dried. Add 60 μL of 50% (v/v) methanol/water solution to dissolve the sample, centrifuge at 4° C. for 5 min at 18000 g, and take the supernatant for RP-HPLC analysis. There are three replicates at each time point, and the peak area of the peptide at each time point is detected using reverse phase high-performance liquid chromatography (RP-HPLC). The ratio of the remaining peak area of the sample at detection time T (h) to the peak area of the prototype peptide at 0 h is calculated as the remaining percentage (%) of the peptide. The negative control shows that the proteins or peptides contained in human serum do not interfere with the detection of the target peptide under this treatment method.
Results: After incubation with human serum for 12 hours, GLP-1 and its analogues remained about 3.5%, which was inconsistent with the reported plasma half-life of only 1-2 minutes. The reason was that GLP-1 was mainly metabolized by metabolic enzymes DPP-IV and NEP24.11 in the systemic circulation, which were membrane proteins and extremely low in normal serum, especially NEP24.11 released in the blood circulation could be used as a biomarker of many physiological and pathological processes. The GLP-1 analogs containing inhibitory peptide scaffolds against trypsin, chymotrypsin and elastase showed high serum stability, and the GLP-1 analogs containing inhibitory peptide scaffolds against trypsin fused both at N-terminus (SEQ ID NO: 194 and SEQ ID NO: 198) and C-terminus (SEQ ID NO: 196 and SEQ ID NO: 200) showed good serum stability; In addition, GLP-1 analogs containing inhibitory peptide scaffolds against chymotrypsin and elastase at C-terminal (SEQ ID NO: 203, SEQ ID NO: 205, SEQ ID NO: 207, SEQ ID NO: 209) are more stable in serum than GLP-1 analogs containing inhibitory peptide scaffolds against chymotrypsin and elastase at N-terminal (SEQ ID NO: 202, SEQ ID NO: 204, SEQ ID NO: 206, SEQ ID NO: 208) (
aThe remaining amount of the sample at this time point did not comply with the degradation
bTwo samples at this time point did not achieve baseline separation.
The day before the experiment, all of the animals were fasted for 15-16 hours with water ad libitum. On the day of the experiment, the animals were randomly divided according to body weight (n=10). Firstly, the blood was collected from the tail tip at 0 hour, and then the animals were administered subcutaneously with GLP-1 analog (SEQ ID NOs: 194-201, 1 μmol/kg) or saline. After 30 minutes, the animals were administered by gavage with glucose solution (2 g/kg), and the blood was collected from the tail tip at 30, 60, and 120 minutes later. Blood glucose was measured using glucose oxidase method. The blood glucose and area under the blood glucose-time curve (AUC) were calculated.
AUC (mg×h/dL)=(BG0+BG30)×30/60+(BG30+BG60)×30/60+(BG60+BG120)×60/60. BG0, BG30, BG60, and BG120 represent blood glucose levels at 0, 30, 60, and 120 minutes after glucose loading, respectively.
Results: Subcutaneous injection of GLP-1 analogues (SEQ ID NO: 194, SEQ ID NO: 196, SEQ ID NO: 198, and SEQ ID NO: 200) containing both inhibitory peptide scaffolds BT9 (SEQ ID NO: 9) and BT45 (SEQ ID NO: 45) against trypsin, and anti-DPP-IV diprotin A (IPI) peptide segments significantly reduced the blood glucose levels at 30, 60, and 120 minutes after oral glucose loading and the AUC in normal ICR mice (
Subcutaneous injection of GLP-1 analogs (SEQ ID NOs: 202-205) containing both anti-chymotrypsin peptide scaffolds CH4 (SEQ ID NO: 84) and CH10 (SEQ ID NO: 90), and the anti-DPP-IV diprotin A (IPI) peptide segments can also significantly reduce the blood glucose levels at 30, 60, and 120 minutes after oral glucose loading and the AUC in normal ICR mice (
Subcutaneous injection of GLP-1 analogues (SEQ ID NOs: 206-209) containing both anti-elastase peptide scaffolds EC1 (SEQ ID NO: 134) and EC12 (SEQ ID NO: 145), and the anti-DPP-IV diprotin A (IPI) peptide segments also significantly reduced the blood glucose levels at 30 and 60 minutes after oral glucose loading and the AUC in normal ICR mice (
Subcutaneous injection of acetylated and amidated GLP-1 analogues (SEQ ID NO: 194, SEQ ID NO: 196, SEQ ID NO: 198, and SEQ ID NO: 200), as well as N-terminal PEG modified GLP-1 analogs (SEQ ID NO: 200 and SEQ ID NO: 204) did not show any significant differences in their hypoglycemic activity compared to the unmodified molecules.
Drug delivery technology can use enteric coating technology to achieve oral administration targeting the small intestine. In order to test the feasibility of direct small intestinal administration of GLP-1, the present invention designs duodenal administration. The experimental process is as follows: The day before the experiment, all of the animals were fasted for 15-16 hours with water ad libitum. On the day of the experiment, the animals were randomly divided according to body weight (n=9-11 or 14-15 for combined administration). Firstly, the blood was collected from the tail tip at 0 hours, and then the animals were anesthetized by inhaling ether. A small incision was made near the underside of the stomach using surgical scissors, and the duodenum was carefully removed and administered with GLP-1 analogs (SEQ ID NOs: 194-209, 10 μmol/kg) or saline. Finally, the wound was sutured. After 15 minutes, the glucose solution (2 g/kg) was administered by gavage, and the blood were collected from the tail tips at 15, 30, and 60 minutes after glucose administration. Blood glucose was measured using the glucose oxidase method. The blood glucose at each moment and area under the blood glucose-time curve (AUC) were calculated.
AUC mg×h/dL)=(BG0+BG15)×15/60+(BG15+BG30)×15/60+(BG30+BG60)×30/60. BG0, BG15, BG30, and BG60 represent blood glucose levels at 0, 15, 30, and 60 minutes after glucose loading, respectively.
Results: Duodenal administration of GLP-1 analogues (SEQ ID NO: 194, SEQ ID NO: 196, SEQ ID NO: 198, SEQ ID NO: 200) containing both anti-trypsin peptide scaffolds BT9 (SEQ ID NO: 9) and BT45 (SEQ ID NO: 45), and anti-DPP-IV diprotin A (IPI) peptide segments in normal ICR mice displayed different results. Compared with the Nor group, duodenal administration of GLP-1 analog D-GLP-1-BT9 (SEQ ID NO: 200) significantly reduced the blood glucose level at 15, 30, and 60 minutes after oral glucose loading and the AUC; Duodenal administration of GLP-1 analog BT1-D-GLP-1 (SEQ ID NO: 194) reduced the blood glucose by 23.2% at 60 minutes without statistical significance; Duodenal administration of GLP-1 analog BT9-D-GLP-1 (SEQ ID NO: 198) reduced the blood glucose at 60 minutes and the AUC by 22.7% and 20.1%, respectively, but also failed statistical tests (
Duodenal administration of GLP-1 analogues (SEQ ID NO: 195, SEQ ID NO: 197, SEQ ID NO: 199, and SEQ ID NO: 201) containing both anti-trypsin peptide scaffolds BT9 (SEQ ID NO: 9) and BT45 (SEQ ID NO: 45), and the anti-NEP24.11 Opiorphin (QRFSR) peptide segment did not influence the blood glucose levels in normal ICR mice after oral glucose loading.
Duodenal administration of GLP-1 analogues (SEQ ID NOs: 202-205) containing both anti-chymotrypsin peptide scaffolds CH4 (SEQ ID NO: 84) and CH10 (SEQ ID NO: 90), and anti-DPP-IV diprotin A (IPI) peptide segments also displayed different results. Compared to Nor, duodenal administration of GLP-1 analogue CH4-D-GLP-1 (SEQ ID NO: 202) significantly reduced the blood glucose at 30 minutes and the AUC in normal ICR mice after oral glucose loading, with a reduction of 32.3% and 23.6%, respectively; Duodenal administration of GLP-1 analogue CH10-D-GLP-1 (SEQ ID NO: 204) significantly reduced the blood glucose at 15 minutes and the AUC in normal ICR mice after oral glucose loading, with a reduction of 20.4% and 15.8%, respectively; Duodenal administration of GLP-1 analogue D-GLP-1-CH10 (SEQ ID NO: 205) also significantly reduced the blood glucose at 15 minutes in normal ICR mice after oral glucose loading, with a reduction of 24.8% (
Duodenal administration of GLP-1 analogues (SEQ ID NOs: 206-209) containing both anti-elastase peptide scaffolds EC1 (SEQ ID NO: 134) and EC12 (SEQ ID NO: 145) and anti-DPP-IV diprotin A (IPI) peptide segment did not reduce the blood glucose or AUC in normal ICR mice after oral glucose loading, indicating that the stability of these GLP-1 analogues to withstand elastase enzymatic hydrolysis increased, but still can't resist the degradation of trypsin and chymotrypsin. However, compared with Nor, duodenal administration of GLP-1 analogue EC12-D-GLP-1 (SEQ ID NO: 208) reduced the blood glucose at 15, 30, and 60 minutes by 11.9%, 19.9% and 17.4%, respectively (
The proteases in the small intestine secreted by the pancreas mainly include trypsin (19% of total protein), chymotrypsin (9% of total protein), and elastase [Whitcomb D C, Low M E. Human pancreatic digestive enzymes. Dig Dis Sci. 2007, 52, 1-17]. In order to detect whether GLP-1 analogues containing different inhibitory peptide scaffolds against serine proteases have combined effects, the effective GLP-1 analogues D-GLP1-BT9 (SEQ ID NO: 200) and CH10-D-GLP-1 (SEQ ID NO: 204) at 10 μmol/kg were selected to perform a dose-effect relationship study. The results showed that duodenal injection of D-GLP1-BT9 and CH10-D-GLP-1 at 2.5 and 5.0 μmol/kg had no significant influence on the blood glucose in normal ICR mice. Then duodenal injection of D-GLP1-BT9 in combination with CH10-D-GLP-1 at 5.0 μmol/kg, as well as combination with CH10-D-GLP-1 and EC12-D-GLP-1 (SEQ ID NO: 208) at 5.0 μmol/kg were performed. The results showed that combination of D-GLP1-BT9 and CH10-D-GLP-1 significantly decreased the blood glucose at 15 minutes after oral glucose loading (p=0.0319) and had a trend of reducing the blood glucose at 30 and 60 minutes after oral glucose loading (p>0.05). To our surprise, combination of D-GLP1-BT9, CH10-D-GLP-1 and EC12-D-GLP-1 significantly reduced the blood glucose at 15, 30 and 60 minutes after oral glucose loading and the AUC (p<0.05) (
Based on the in vivo activity study of GLP-1 analogues containing inhibitory peptide scaffolds against serine protease, in order to further study whether these peptide scaffolds can be widely used to improve the efficacy of other therapeutic peptides, a series of polypeptides were designed and synthesized, so as to reach the ability of Pep2-8 (PCSK9_1, SEQ ID NO: 210) to inhibit PCSK9-LDLR interactions (Table 23).
Polypeptide PCSK9_1-14 (SEQ ID NOs: 210-223) is dissolved in pure water or DMSO. 85 μL reaction buffer, 5 μL 1 mM polypeptide sample and 10 μL 750 ng/mL PCSK9 protein was pre-incubated at room temperature for 20 minutes before being added to a 96 well plate. The OD450/540 nm value was measured according to the instructions of the PCSK9-LDLR in Vitro Binding Assay Kit (CY-8150, MBL Company, Beijing, China). Solvent control: replace polypeptide with 5 μL solvent. In 100 μL reaction system, the final concentration of the polypeptide and PCSK9 is 50 μM and 75 ng/mL, respectively.
Inhibition rate of polypeptide (%)=(OD450/540 nm(solvent control)−OD450/540 nm (sample))/OD450/540 nm(solvent control)×100
Results: At a final concentration of 50 μM, the polypeptides PCSK9_2, PCSK9_3, PCSK9_5, PCSK9_6, PCSK9_7 and PCSK9_8 that contain the anti-trypsin peptide scaffold BT9 and the peptide PCSK9_9 that contains the anti-trypsin peptide scaffold BT45 have good inhibitory activity on the interaction between PCSK9 and LDLR in comparison to the reported PCSK9_1. The peptides PCSK9_2CH, PCSK9_2EC, PCSK9_3CH, PCSK9_3EC, PCSK9_5CH, PCSK9_5EC, PCSK9_6CH, PCSK9_6EC, PCSK9_9CH and PCSK9_9EC that contains the anti-chymotrypsin and anti-elastase peptide scaffolds CH10 and EC12 also displayed good inhibitory activity on the interaction between PCSK9 and LDLR (Table 24). These results showed that the inhibitory peptide scaffolds against trypsin, chymotrypsin and elastase (BT9, BT45, CH10, and EC12) increased the inhibitory effect of peptide Pep2-8 (PCSK9_1) on the interaction between PCSK9 and LDLR by 2-3 times; Especially the high similarity between the anti-trypsin peptide scaffolds and the anti-chymotrypsin and anti-elastase peptide scaffolds in PCSK9_9 indicated that the inhibitory peptide scaffolds against chymotrypsin and elastase can also enhance the activity of Pep2-8 (PCSK9_1) to inhibit the interaction between PCSK9 and LDLR.
FCTYSIPPQCYGGTVFTSWEEALDWV
ICTASIPPICQGTVFTSWEEALDWV
aIn the table, the scaffolds of anti-trypsin, anti-chymotrypsin, and anti-elastase are named BT, CH, and EC, respectively, and are marked with dashed lines, double lines, and italics, respectively. In addition, disulfide bonds are formed between two cysteine residues of the three scaffolds in the polypeptide sequence.
aThe concentration of samples in the table was 50 μM. When measuring the IC50 value, the sample with strong inhibitory activity was directly measured at 10 and 100 μM.
Model preparation and validation: Normal ICR mice were fasted overnight with water ad libitum. The poloxamer 407 (P407, 500 mg/kg) was intraperitoneally injected on the next day. After 24 hours, serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels were significantly increased. The clinical drug Repatha was injected subcutaneously at a dose of 40 mg/kg for 24 hours, followed by intraperitoneal injection of P407. The serum TC and LDL-C levels were measured 24 hours after injection of P407 (Table 25). The results showed that intraperitoneal injection of P407 significantly increased the serum TC and LDL-C levels in ICR mice, and subcutaneous injection of Repatha (40 mg/kg) significantly reduced the serum TC and LDL-C levels.
The experimental peptide sample was prepared using PEG400 with a final concentration of 2 mol/kg, and the final concentration of PEG400 is 20% (w/v). Normal ICR mice were fasted overnight with water ad libitum. The next day, all of the mice were randomly divided into model control group (Con) and polypeptide administration group (2 μmol/kg) according to body weight. Then, all of the mice were intraperitoneally injected with P407 (500 mg/kg) and fed with feed 2 hours later. Six mice were taken as a normal control group (Nor). After 24 hours, the mice in Con were subcutaneously injected with saline containing 20% PEG400, and the mice in the treatment group were given peptides. Then, the blood was taken at different time points after administration to determine the serum total cholesterol (TC) level. In consideration of the complexity of factors affecting serum LDL-C levels, especially the differences between single and long-term administration, the in vivo activity of PCSK9 inhibitory peptide is mainly observed for changes in serum TC levels.
The results showed that the serum TC level of mice in Con group was significantly increased in comparison to Nor, indicating that the model was successful. In comparison to Con, single subcutaneous injection of PCSK9_5, PCSK9_6, PCSK9_9, PCSK9_5EC, PCSK9_6CH and PCSK9_6EC had a reduced serum TC level (Table 26).
Enteric coating technology can be used to achieve oral delivery of drugs targeted small intestine. Considering factors such as gastric emptying and physical barriers to the stomach, in order to accurately detect the feasibility of direct delivery of targeted PCSK9 inhibitory peptide to the small intestine, duodenal delivery is designed. The experimental process is as follows:
The experimental polypeptide sample was prepared using PEG400 with a final concentration of 20 μmol/kg and the final concentration of PEG400 is 50% (w/v). The control group was saline containing PEG400 (50%).
Normal ICR mice were fasted overnight with water ad libitum. The next day, all of the mice were intraperitoneally injected with poloxamer 407 (P407, 500 mg/kg) to establish a model of lipid metabolism disorder. Six mice were intraperitoneally injected with saline as a normal control (Nor). Normal feeding resumed after 2 hours. The model animals were randomly divided into model group (Con) and polypeptide groups according to body weight, and the blood was collected from tail tip (0 min). Then, the animals were anesthetized with ether for duodenal exposure surgery. At the same time, a sample or saline containing PEG400 was injected through the duodenum. Finally, the wound was sutured. The blood was collected from tail tip at 15, 30, 60, and 90 minutes after administration to determine the serum total cholesterol level.
Results: Based on the in vivo activity of subcutaneous injection of the inhibitory peptide targeting PCSK9, PCSK9_6, PCSK9_6CH and PCSK9_6EC was used as test peptides in the duodenal administration experiment. The results showed that peptides PCSK9_6, PCSK9_6CH and PCSK9_6EC at the dose of 20 mol/kg did not show hypolipidemic activity (Table 27). The reason may be that the purity of the synthesized sample is poor, and the prototype polypeptide PCSK9_1 (Pep2-8) itself has shown little effect on lowering total cholesterol during subcutaneous injection experiments.
Referring to the experimental method in Example 5, the enzymatic stability of the PCSK9 inhibitory peptide that was effective in vivo after subcutaneous injection was evaluated in vitro.
Results: PCSK9_1 was easily degraded by chymotrypsin and elastase but was stable towards trypsin for deficiency of basic amino acids in the molecule. PCSK9_6 that displayed lipid-lowering activity in vivo was selected as a representative to analyze its stability against chymotrypsin and elastase. The results showed that although it only contains inhibitory peptide scaffolds against trypsin, it also had certain inhibitory effects on the other two proteases chymotrypsin and elastase (Tables 28 and 29). It also indicates that the promiscuity activity of peptide scaffolds exerts the cross-inhibitory reactivity against chymotrypsin and elastase.
Salmon Calcitonin is a peptide drug for the treatment of senile osteoporosis and osteoarthritis, and the effect is relatively definite. The clinical dosage forms are injection and nasal spray. In order to confirm whether the inhibitory peptide scaffolds against serine protease can improve the efficacy of salmon Calcitonin after oral administration, its analogs containing different inhibitory peptide scaffolds were designed and synthesized (Table 30).
YG
aThe skeletons of anti-trypsin, anti-chymotrypsin and anti-elastase are named BT, CH and EC, respectively, which are marked with dotted lines, double lines and italics. In addition, disulfide bonds are formed between the two cysteine residues in these three skeletons of the peptide sequences.
Referring to the experimental method in Example 5, in vitro stability of salmon Calcitonin analogs with oral administration activity to the enzymatic hydrolysis by trypsin, chymotrypsin and elastase were performed.
Results: Salmon Calcitonin analogues (CalM) were extremely unstable towards trypsin, and most of them were degraded after 3 min of co-incubation; CalM exhibited certain stability towards chymotrypsin, with approximately 4.9% of the prototype peptide remaining after 60 minutes of co-incubation. Salmon Calcitonin analogs Cal-BT, Cal-CH and Cal-EC containing inhibitory peptide scaffolds against serine proteases were resistant to the corresponding protease degradation, respectively. Cal-BT not only tolerated the degradation of trypsin, but also had high tolerance to chymotrypsin; Cal-EC had a certain tolerance to chymotrypsin (Tables 31 and 32).
Rats were fasted for 12 hours with water ad libitum before the experiment. The animals were randomly divided into 4 groups (5 animals in each group). The normal control group was injected with normal saline solution, and the commercially available salmon Calcitonin (sCat) and synthetic Calcitonin analog (CalM) were injected subcutaneously. The capsule form Cal BT (1 umol/kg, p.o.) was administered by gavage.
Take blood from the inner canthus of rats at the predetermined time points: 0, 2, 3, 4, 6, 8, 12, and 24 h later, with at least 0.2 mL of blood taken each time. The blood sample was placed at 4° C. for stratification and centrifuged at 3000 rpm for 10 minutes. The serum was separated and measured for serum calcium ion concentration.
The serum calcium ion concentration at 0 h was considered as baseline, the blood calcium concentration at other time was converted into the percentage ratio of baseline. The blood calcium curve was drawn with time as the X axis and the percentage of blood calcium concentration (%) as the Y axis.
Results: The changes of body weight were shown in Table 33; Using the decrease in blood calcium concentration at different times as the evaluation criteria, the results showed that the commercially available salmon Calcitonin (sCat) could effectively reduce the concentration of calcium ions in rats 3, 4, 6, 8, 12 and 24 hours after administration. Salmon Calcitonin analogue (CalM) can effectively reduce the concentration of calcium ions in rats 3 hours after administration, but the capsule form Cal BT did not effectively reduce the concentration of calcium ions in rats (
Based on the in vivo activity study of GLP-1 analogues containing inhibitory peptide scaffolds against serine proteases, in order to further investigate whether these peptide inhibitors can be widely used to improve the efficacy of other therapeutic peptides, a series of inhibitory peptides targeting IL-17A (Table 34) were designed and synthesized with the research goal of 17A (SEQ ID NO: 238), which has inhibitory effects on IL-17A.
PQCYG
ICQ
aThe skeletons of anti-trypsin, anti-chymotrypsin and anti-elastase are named BT, CH and EC, respectively, which are marked with dotted lines, double lines and italics. In addition, disulfide bonds are formed between the two cysteine residues in these three skeletons of the peptide sequences.
Referring to the experimental method in Example 5, in vitro stability of IL-17A inhibitory peptides towards the enzymatic hydrolysis by trypsin, chymotrypsin and elastase were performed.
Results: Peptide 17A is unstable towards chymotrypsin and elastase, but very stable towards trypsin, because there are no basic amino acids in the molecule; peptides 17A-BT, 17A-CH, and 17A-EC with the inhibitory peptide scaffolds against serine proteases separately tolerated to the degradation of corresponding serine proteases, and also exhibited certain inhibitory effects on the other two serine proteases (Table 35).
IL-17A is an inflammatory factor in many chronic inflammatory reactions. In order to quickly evaluate and analyze its anti-inflammatory effects, a mouse ear swelling model was first used for preliminary screening of anti-inflammatory activities. The experimental process is as follows. Kunming male mice (18-20 g, n=10) were labeled with picric acid. All mice in each group were coated with 10 μL croton oil on both sides of the right ear. Immediately after modeling, the positive drugs Secukinumab group (5 mg/kg), inhibitory peptides 17A, 17A-BT, 17A-CH, and 17A-EC (30 mg/kg) were subcutaneously injected. The model control group (Con) was injected with a corresponding volume of physiological saline. After causing inflammation for 4 hours, the mice in each group were killed for cervical dislocation, and then the ear pieces were punched in the symmetrical parts of the left and right ears with a hole punch. The weight was weighed and recorded. The swelling degree and swelling rate were calculated:
Swelling rate=((right ear mass−left ear mass)/left ear mass)*100%
Results: Targeted IL-17A inhibitory peptides 17A-BT and 17A-CH administered (30 mg/kg) subcutaneously can significantly inhibit the inflammatory response to ear swelling induced by croton oil, while 17A and 17A-EC have no inhibitory effect, indicating that the inhibitory peptide scaffolds against serine protease can effectively improve the stability of the IL-17A inhibitory peptide in the blood circulation, thereby improving its efficacy in vivo (Table 36).
Enteric coating technology can be used to achieve oral administration of targeted small intestine drugs. Considering factors such as gastric emptying and physical barriers in the stomach, in order to accurately detect the feasibility of direct intestinal administration of targeted IL-17A inhibitory peptide, duodenal administration is designed. Eight mice in each group are subjected to surgical exposure of the duodenum under ether anesthesia, and the drug is injected according to different grouping schemes.
The model control group (Con) is given PEG400 (50%, w/v)/physiological saline. The administration group was given different polypeptide samples (300 mg/kg), while the positive control group was given dexamethasone (1 mg/mL, 10 mL/kg), and then the muscular layer and cortex were sutured. Ear swelling model was established 6 minutes after suture. All mice in each group were coated with 10 μL croton oil on both sides of the right ear. After 4 hours of inflammation, the mice in each group were killed for cervical dislocation. After that, ear pieces were punched in the symmetrical parts of the left and right ears with a hole punch and weighed. Their mass was recorded. The swelling degree and swelling rate were calculated:
Swelling rate=((right ear mass−left ear mass)/left ear mass)*100%
Results: Compared with the model control group, the inhibitory effects of the inhibitory peptides 17A-BT (P<0.01) and 17A-CH (P<0.05) targeting IL-17A on mouse ear swelling via duodenal administration were statistically significant (Table 37).
Fill the capsules (size M, Torpac) with bromophenol blue powder as a tracer for enteric coating. Soak 2/3 of the capsule surface in the coating material Eudragit L100-55 mixture (Eudragit L100-55/0.9 g, PEG 400/0.14 g, Tween 80/0.01 g, acetone/3.8 mL, isopropanol/5.7 mL, water/0.5 mL) for 15 seconds and dry for 30 minutes. Turn it upside down again, operate the remaining 1/3 of the capsule surface in the same way, repeat soaking 3 times, and dry at room temperature in a fume hood for 72 hours. Then immerse the capsule coated with enteric coating in simulated gastric fluid (pH 1.6) for 2 hours, or in simulated intestinal fluid (pH 6.5) for 1 hour. Monitor the amount of bromophenol blue released by capsule disintegration as the immersion time increases, i.e., measure the absorption at 422 nM to determine the effectiveness of capsule encapsulation. The results indicated that the thickness of the capsule coating is 0.16+0.05 nm; The release of bromophenol blue was 2.8˜6.5% (92˜97% remained intact) after 2 hours of incubation in simulated gastric juice, and 44˜51.3% after 1 hour of incubation in simulated intestinal juice.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202011396904.2 | Nov 2020 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2021/134179 | 11/29/2021 | WO |
