Patent Grant
10927360
The instant application contains a Sequence Listing which has been submitted in ASCII format via EFS-Web and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Jun. 1, 2020, is named 49160-716.201_ST25.txt and is 33,680 bytes in size.
Pepsin is a protease that cleaves polypeptides into smaller units. In nature, pepsin is a digestive enzyme found in the stomach of animals and humans, that helps to digest food. Outside of its naturally-occurring environment, pepsin is used as a processing enzyme in a variety of applications. For example, pepsin can be used to modify food ingredients, it is a component in cheese making, used in the leather industry and also used to prepare antibody fragments used for pharmaceutical and biotechnology applications.
Pepsin is expressed as a zymogen pepsinogen, which has additional amino acids as compared with pepsin. Under non-acidic pH condition, pepsinogen is activimmature, due to the presence of the propeptide. Under acidic pH conditions, pepsinogen can unfold and cleave itself to create the mature form of the enzyme which is pepsin. Typically, the enzyme is extracted from pig stomach. Because the stomach is an acidic environment, the extracted form is primarily the cleaved and active pepsin form.
An aspect of the present disclosure is a composition comprising a recombinant pepsin polypeptide. The composition is (a) free from animal-derived proteins, (b) the pepsin polypeptide is substantially in an intact and stable proteolytically inactive form, (c) the composition has a pH greater than about 5.4, and (d) the composition has a specific activity at pH of 2 of at least 30,000 FCC units/mg total protein.
In some embodiments, the composition is in powdered form. The proteolytically inactive pepsin polypeptide form may be stable in the composition for at least 6 months at room temperature. The proteolytically inactive pepsin polypeptide form is stable in the composition for at least 6 months at 4° C. The composition may have a moisture content of less than about 10%.
In some embodiments, the composition has a specific activity at pH of 2 of at least 40,000 FCC units/mg total protein, e.g., at least 50,000 FCC units/mg total protein, at least 60,000 FCC units/mg total protein, and at least 70,000 FCC units/mg total protein. In embodiments, an FCC unit (also referred to herein as a pepsin unit) is defined as that quantity of enzyme that produces the equivalent of 1 μmol of tyrosine per min under the conditions of incubating the enzyme with 2% hemoglobin substrate at pH 1.6 for 10 minutes at 25° C. (see Food Chemical Codex, 11th ed. (Pharmacopeial Convention. 2018) at 1386-87 “Pepsin Activity”).
In some embodiments, the composition has a pH of at least about 6.0.
In some embodiments, the composition is in liquid form. The concentration of the recombinant pepsin polypeptide may be at least 20 g per liter. The proteolytically inactive pepsin polypeptide form may be stable in the composition for at least 30 days at a temperature of about 4° C.
In some embodiments, the recombinant pepsin polypeptide comprises an amino acid sequence of a sheep, pig, cow, human, zebu, yak, Central European red deer or goat pepsin.
In some embodiments, the recombinant pepsin polypeptide comprises SEQ ID NO: 10, or an amino acid sequence with at least 90% identity thereto.
In some embodiments, the recombinant pepsin polypeptide is produced in a yeast, a filamentous fungi, a Saccharomyces species, a bacteria, a Pichia species, a Trichoderma species or an Aspergillus species. In embodiments, the recombinant pepsin polypeptide is produced in Pichia sp.
A composition may be produced by a method comprising steps of (a) providing a microorganism expressing a recombinant pepsinogen, wherein the expressed pepsinogen is secreted by the microorganism into a growth media; (b) harvesting the growth media and removing the cells therefrom to obtain a liquid starting material; (c) lowering the pH of the liquid starting material to less than pH 4.0 to obtain an activated pepsin composition; and (d) raising the activated pepsin composition to a pH of about 6.0 to obtain the composition comprising the recombinant pepsin polypeptide.
In some embodiments, the recombinant pepsinogen comprises one of SEQ ID NOs: 1-9, or an amino acid sequence with at least 90% identity thereto.
Another aspect of the present disclosure is a method of producing a high-activity stable pepsin composition. The method comprising steps of (a) providing a microorganism expressing a recombinant pepsinogen, wherein the expressed pepsinogen is secreted by the microorganism into the growth media; (b) harvesting the growth media and removing the cells therefrom to obtain a liquid starting material; (c) lowering the pH of the liquid starting material to less than pH 4.0 to obtain an activated pepsin composition; and (d) raising the activated pepsin composition to a pH of about 6.0 to obtain a high-activity stable pepsin composition.
In some embodiments, the method further comprises a step of isolating the activated pepsin polypeptide from protein and small molecules in the liquid starting material after steps (c) and (d), i.e., after (c) lowering the pH of the liquid starting material to less than pH 4.0 to obtain an activated pepsin composition and (d) raising the activated pepsin composition to a pH of about 6.0 to obtain a high-activity stable pepsin composition.
The high-activity stable pepsin composition produced by the method may comprise an intact and stable proteolytically inactive form of the pepsin polypeptide and a pH greater than about 5.4 and the composition may have a specific activity at pH of 2 of at least 30,000 FCC units/mg total protein.
The high-activity stable pepsin composition produced by the method may comprise a pepsin polypeptide having an amino acid sequence of a sheep, pig, cow, human, zebu, yak, Central European red deer, or goat pepsin.
In some embodiments, the microorganism that expresses a recombinant pepsinogen is a yeast, a filamentous fungi, a Saccharomyces species, a bacteria, a Pichia species, a Trichoderma species or an Aspergillus species.
Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
Additionally, any composition or method disclosed herein is applicable to any herein-disclosed composition or method. In other words, any aspect or embodiment described herein can be combined with any other aspect or embodiment as disclosed herein.
All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
Provided herein are compositions and methods for making compositions comprising pepsin.
An aspect of the present disclosure is a composition comprising a recombinant pepsin polypeptide. The composition is (a) free from animal-derived proteins, (b) the pepsin polypeptide is substantially in an intact and stable proteolytically inactive form, (c) the composition has a pH greater than about 5.4, and (d) the composition has a specific activity at pH of 2 of at least 30,000 FCC units/mg total protein.
Another aspect is a method for producing a recombinant pepsin composition. The method comprises steps of (a) providing a microorganism expressing a recombinant pepsinogen, wherein the expressed pepsinogen is secreted by the microorganism into a growth media; (b) harvesting the growth media and removing the cells therefrom to obtain a liquid starting material; (c) lowering the pH of the liquid starting material to less than pH 4.0 to obtain an activated pepsin composition; and (d) raising the activated pepsin composition to a pH of about 6.0 to obtain the composition comprising the recombinant pepsin polypeptide.
Expression of Pepsinogen
The protein pepsinogen refers to an immature form of the protein pepsin and carries a propeptide. Upon maturation, the propeptide is cleaved off to produce pepsin. The mature form pepsin may be enzymatically active under certain conditions, such as low pH. In some embodiments, compositions containing the mature form of a recombinant pepsin, when placed under activation conditions, provide a high level of enzymatic activity.
Provided herein are methods for producing compositions of recombinant pepsin that are stable and can be activated to a high level of specific activity. The methods herein comprise a step of expressing recombinant pepsinogen in a host cell. As used herein, a “host” or “host cell” denotes here any protein production host selected or genetically modified to produce a desired product. Exemplary hosts include fungi, such as filamentous fungi, as well as bacteria, yeast, plant, insect, and mammalian cells. A host cell may be Arxula spp., Arxula adeninivorans, Kluyveromyces spp., Kluyveromyces lactis, Komagataella phaffii, Pichia spp., Pichia angusta, Pichia pastoris, Saccharomyces spp., Saccharomyces cerevisiae, Schizosaccharomyces spp., Schizosaccharomyces pombe, Yarrowia spp., Yarrowia lipolytica, Agaricus spp., Agaricus bisporus, Aspergillus spp., Aspergillus awamori, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, Aspergillus oryzae, Bacillus subtilis, Colletotrichum spp., Colletotrichum gloeosporiodes, Endothia spp., Endothia parasitica, Escherichia coli, Fusarium spp., Fusarium graminearum, Fusarium solani, Mucor spp., Mucor miehei, Mucor pusillus, Myceliophthora spp., Myceliophthora thermophila, Neurospora spp., Neurospora crassa, Penicillium spp., Penicillium camemberti, Penicillium canescens, Penicillium chrysogenum, Penicillium (Talaromyces) emersonii, Penicillium funiculosum, Penicillium purpurogenum, Penicillium roqueforti, Pleurotus spp., Pleurotus ostreatus, Rhizomucor spp., Rhizomucor miehei, Rhizomucor pusillus, Rhizopus spp., Rhizopus arrhizus, Rhizopus oligosporus, Rhizopus oryzae, Trichoderma spp., Trichoderma altroviride, Trichoderma reesei, or Trichoderma vireus. A host cell can be an organism that is approved as generally regarded as safe by the U.S. Food and Drug Administration.
In some embodiments, the host cell for recombinant pepsinogen production can be a Pichia species (Komagataella phaffii and Komagataella pastoris), a Saccharomyces species, a Trichoderma species, a Pseudomonas species or an E. coli species. In some embodiments, pepsinogen is expressed in a Pichia species, such as Komagataella phaffii.
The recombinant expression of pepsinogen in a host cell can be regulated by a promoter. Promoters include, but are not limited to, acu-5, adh1+, alcohol dehydrogenase (ADH1, ADH2, ADH4), AHSB4m, AINV, alcA, α-amylase, alternative oxidase (AOD), alcohol oxidase I (AOX1), alcohol oxidase 2 (AOX2), AXDH, B2, CaMV, cellobiohydrolase I (cbh1), ccg-1, cDNA1, cellular filament polypeptide (cfp), cpc-2, ctr4+, CUP1, dihydroxyacetone synthase (DAS), enolase (ENO, ENO1), formaldehyde dehydrogenase (FLD1), FMD, formate dehydrogenase (FMDH), G1, G6, GAA, GAL1, GAL2, GAL3, GAL4, GAL5, GAL6, GAL7, GAL8, GAL9, GAL10, GCW14, gdhA, gla-1, α-glucoamylase (glaA), glyceraldehyde-3-phosphate dehydrogenase (gpdA, GAP, GAPDH), phosphoglycerate mutase (GPM1), glycerol kinase (GUT1), HSP82, invl+, isocitrate lyase (ICL1), acetohydroxy acid isomeroreductase (ILV5), KAR2, KEX2, β-galactosidase (lac4), LEU2, melO, MET3, methanol oxidase (MOX), nmt1, NSP, pcbC, PETS, peroxin 8 (PEX8), phosphoglycerate kinase (PGK, PGK1), pho1, PHO5, PHO89, phosphatidylinositol synthase (PIS1), PYK1, pyruvate kinase (pki1), RPS7, sorbitol dehydrogenase (SDH), 3-phosphoserine aminotransferase (SER1), SSA4, SV40, TEF, translation elongation factor 1 alpha (TEF1), THI11, homoserine kinase (THR1), tpi, TPS1, triose phosphate isomerase (TPI1), XRP2, YPT1, In some embodiments of the methods, the expression of pepsinogen is achieved by regulating the expression using an inducible promoter. Exemplary inducible promoters that can be used for expression include, but are not limited to methanol inducible promoters, such as alcohol oxidase promoters AOX1 and AOX2, and sugar inducible promoters such as glucose-induced and rhamnose regulated promoters.
In some embodiments, the recombinant pepsinogen expressed in the host cell is secreted without conversion to a proteolytically active form such that the recombinant pepsinogen is present in and can be isolated from the growth media in which the host cell is grown. Secretion of recombinant pepsinogen can be achieved by including a secretion signal in the expression construct, which can be cleaved off as the polypeptide is transited through the host cell secretory pathway. In some embodiments, the secretion signal is present at the N-terminus of the recombinant pepsinogen polypeptide (for example, the bolded sequence in SEQ ID NO: 1). Exemplary secretion signals include but are not limited to the mating factor α-factor pro sequence from Cerevisiae, an Ost1 signal sequence, hybrid Ost1-α-factor pro sequence, and synthetic signal sequences. In some embodiments, the pepsinogen expression constructs include a heterologous secretion signal (e.g., not derived natively from pepsinogen). In some embodiments, the pepsinogen expression constructs include a heterologous secretion signal and lack any secretion signal naturally-derived from or associated with a native pepsinogen coding sequence.
Expression constructs can also include transcriptional terminators. Exemplary transcriptional terminator elements include, but are not limited to, acu-5, adh1+, alcohol dehydrogenase (ADH1, ADH2, ADH4), AHSB4m, AINV, alcA, α-amylase, alternative oxidase (AOD), alcohol oxidase I (AOX1), alcohol oxidase 2 (AOX2), AXDH, B2, CaMV, cellobiohydrolase I (cbh1), ccg-1, cDNA1, cellular filament polypeptide (cfp), cpc-2, ctr4+, CUP1, dihydroxyacetone synthase (DAS), enolase (ENO, ENO1), formaldehyde dehydrogenase (FLD1), FMD, formate dehydrogenase (FMDH), G1, G6, GAA, GAL1, GAL2, GAL3, GAL4, GAL5, GAL6, GAL7, GAL8, GAL9, GAL10, GCW14, gdhA, gla-1, α-glucoamylase (glaA), glyceraldehyde-3-phosphate dehydrogenase (gpdA, GAP, GAPDH), phosphoglycerate mutase (GPM1), glycerol kinase (GUT1), HSP82, invl+, isocitrate lyase (ICL1), acetohydroxy acid isomeroreductase (ILV5), KAR2, KEX2, β-galactosidase (lac4), LEU2, melO, MET3, methanol oxidase (MOX), nmt1, NSP, pcbC, PETS, peroxin 8 (PEX8), phosphoglycerate kinase (PGK, PGK1), pho1, PHO5, PH089, phosphatidylinositol synthase (PIS1), PYK1, pyruvate kinase (pki1), RPS7, sorbitol dehydrogenase (SDH), 3-phosphoserine aminotransferase (SER1), SSA4, SV40, TEF, translation elongation factor 1 alpha (TEF1), THI11, homoserine kinase (THR1), tpi, TPS1, triose phosphate isomerase (TPI1), XRP2, and YPT1.
Pepsinogen coding sequences for use in producing recombinant pepsinogen include animal pepsinogen sequences such as human, bovine, porcine, ovine, and equine. In some embodiments, a pepsinogen sequence is one of SEQ ID NOs: 1-9. The below table also includes the amino acid sequence for an active pepsin (SEQ ID NO: 10).
MKWLLLLSLVVLSECLVKVPLVRKKSLRQNLIKNGKLKDFL
Ovis aries (sheep)
Cervus elaphus
hippelaphus
Capra hircus
Bos taurus
Homo sapiens
Bos mutus (yak)
Bos indicus (Zebu)
A recombinant pepsinogen or recombinant pepsin can include additional sequences. Expression of recombinant pepsinogen or recombinant pepsin in a host cell, for instance a Pichia species, a Saccharomyces species, a Trichoderma species, a Pseudomonas species may lead to an addition of peptides to the pepsinogen or pepsin sequence as part of post-transcriptional or post-translational modifications. Such peptides may not be part of the native pepsinogen or pepsin sequences. For instance, expressing a pepsinogen sequence in a Pichia species, such as Komagataella phaffii and Komagataella pastoris may lead to addition of a peptide at the N-terminus or C-terminus. In some cases, a tetrapeptide EAEA (SEQ ID NO: 11) is added to the N-terminus of the pepsinogen sequence upon expression in a host cell. In some embodiments, pepsinogen or pepsin or both include the amino acids EAEA (SEQ ID NO: 11) at the N-terminus for example, in SEQ ID NO: 2.
A recombinant pepsinogen polypeptide can be a non-naturally occurring variant of a pepsinogen. Such a variant can comprise one or more amino acid insertions, deletions, or substitutions relative to a native pepsinogen sequence.
Similarly, a recombinant pepsin polypeptide can be a non-naturally occurring variant of a pepsin. Such a variant can comprise one or more amino acid insertions, deletions, or substitutions relative to a native pepsin sequence. Variants of pepsinogen can have at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NOs: 1-9 and variants of pepsin can have at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO: 10. The term “sequence identity” as used herein in the context of amino acid sequences is defined as the percentage of amino acid residues in a candidate sequence that are identical with the amino acid residues in a selected sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part of the sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN, ALIGN-2 or Megalign (DNASTAR) software. Those skilled in the art can determine appropriate parameters for measuring alignment, including any algorithms needed to achieve maximal alignment over the full-length of the sequences being compared.
In some embodiments, a variant is one that confers additional features, such as reduced allergenicity. Depending on the host organism used to express the recombinant pepsinogen, it can have a glycosylation, acetylation, or phosphorylation pattern different from wildtype pepsinogen and/or wildtype pepsin. For example, the recombinant pepsinogen or recombinant pepsin disclosed herein may or may not be glycosylated, acetylated, or phosphorylated. A recombinant pepsinogen or a recombinant pepsin may have an avian, non-avian, microbial, non-microbial, mammalian, or non-mammalian glycosylation, acetylation, or phosphorylation pattern.
In some cases, recombinant pepsinogen or recombinant pepsin may be deglycosylated (e.g., chemically, enzymatically, Endo-H, PNGase F, O-Glycosidase, Neuraminidase, β1-4 Galactosidase, β-N-acetylglucosaminidase), deacetylated (e.g., protein deacetylase, histone deacetylase, sirtuin), or dephosphorylated (e.g., acid phosphatase, lambda protein phosphatase, calf intestinal phosphatase, alkaline phosphatase). Deglycosylation, deacetylation or dephosphorylation may produce a polypeptide that is more uniform or is capable of producing a composition with less variation.
Production of Pepsinogen
The pepsinogen expression constructs and host cells can be used to produce recombinant pepsinogen in liquid culture, such as in a test tube, shaker flask, or small-scale and large-scale fermentation vessel. In the methods provided herein, the host cell carrying the pepsinogen expression construct can be initially cultured under conditions where there is little to no expression of pepsinogen as a starter culture, and grown to a target cell number, density or for a target duration (referred to as a “growth phase”).
In some embodiments of the method, after such growth phase, recombinant pepsinogen expression can be initiated (“expression phase”). In some embodiments, expression is initiated such as by induction of an inducible promoter. In some embodiments, expression is initiated such as by release of a repressible promoter or by removal of a blocking sequence, protein binding or other form of repression of expression. In other cases, the expression of pepsinogen can be driven by a constitutive promoter.
In some embodiments, the pH of the culture media is controlled during the growth phase, the expression phase, or during both phases. In some embodiments, the pH of the growth phase is about pH 5. In some embodiments, the pH of the growth media is about 5, and then is increased to about pH 6 before the expression phase.
After initiation of the expression phase, the culturing is continued for a target length of time or up until a target amount of recombinant pepsinogen is recovered from the culture media. In the methods disclosed herein, the cultured host organism can provide a titer of at least about 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 g/L of total protein.
By producing pepsinogen recombinantly, the ultimate recombinant pepsin composition will comprise fewer additional and contaminating proteins, for example when compared to extracting pepsin from natural sources. In particular, when extracting pepsin from natural sources, contaminating animal proteins will be included in the extract. In embodiments, a recombinant pepsin composition may comprise less than 5% of impurities/contaminating proteins, i.e., non-pepsin proteins. For example, a recombinant pepsin composition may comprise less than 4.5%, 4.0%, 3.5%, 3.0%, 2.5%, 2.0%, 1.5%, 1.0%, 0.5% or less of contaminating proteins. In preferred embodiments, a recombinant pepsin composition comprises little to no contaminating animal proteins. In preferred embodiments, a recombinant pepsin composition is free from animal-derived proteins.
Recombinant pepsin compositions of the present disclosure may include additional proteins, e.g., proteins that are added to promote desirable qualities and features to a composition.
Pepsinogen Protein Isolation and Conversion to Pepsin
The methods herein can include one or more steps whereby the recombinant pepsinogen is separated from the host cell and other culture media components. Host cells, some host cell proteins, and cellular debris can be removed through centrifugation, filtration or a combination thereof. However, such gross separation of the host cell and other culture media components does not result in a purified recombinant pepsinogen composition and/or an isolated recombinant pepsinogen composition as additional proteins and other molecules remain in the composition that contains the pepsinogen.
In some embodiments, a composition comprises recombinant pepsinogen in its stable zymogen (inactive) form that can be activated under specific conditions. Such compositions provide improved stability and control of activity upon conversion to a proteolytically active form as compared to the proteolytically active enzyme extracted from animal gut and other sources.
In some embodiments, a composition contains recombinant pepsinogen in a stable, inactive form and the compositions are substantially recombinant pepsinogen and contain low amounts or little to no recombinant pepsin. In some embodiments, the compositions have a ratio of recombinant pepsinogen to recombinant pepsin of at least about 10:1, 100:1, 1000:1 or greater than 1000:1.
In some embodiments, methods for producing a composition of the present disclosure include one or more pH shift steps to convert recombinant pepsinogen to recombinant pepsin and to maintain recombinant pepsin in a stable form. The recombinant pepsinogen compositions disclosed herein can be activated to convert the recombinant pepsinogen to the pepsin form of the enzyme, such as by lowering the pH of the composition, by addition of an acidic ingredient, addition of acid, or by placing the composition in an acidic environment. In some embodiments, in a first pH shift step, the pH can be lowered below pH 5, such as to about pH 4 or pH 3.5 or pH 2.0 for a period of time to convert recombinant pepsinogen to recombinant pepsin. Such a pH shift can be performed at room temperature or at about 20° C. to about 25° C. or at a temperature at or about 10° C.-45° C. In some embodiments, the duration for treating at a pH below 5, e.g., about pH 4 or about pH 3.5, is about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 minutes. In some embodiments, the duration for treating at a pH below 5, e.g., about pH 4 or about pH 3.5, is about 1 hour, 2 hours, 2.25 hours, or 2.5 hours.
In preferred embodiments, growth media comprising recombinant pepsinogen is harvested and cellular material is removed, thereby obtaining a liquid starting material. The pH of the liquid starting material is lowered to less than pH 4.0 (such as pH 3.5) to obtain an activated recombinant pepsin composition. The pH may be lowered by the addition of an acid, for example hydrochloric acid, phosphoric acid, sulfuric acid, or nitric acid. Thus, in embodiments, it is unnecessary to first purify the recombinant pepsinogen, e.g., from a growth media, before converting the recombinant pepsinogen to recombinant pepsin. Surprisingly, a purer recombinant pepsin product which has higher activity is provided by converting newly-synthesized recombinant pepsinogen to recombinant pepsin and subsequently purifying the recombinant pepsin rather than purifying the recombinant pepsinogen.
In embodiments, the compositions are composed of primarily recombinant pepsin and have little or no detectable pepsinogen or other intermediates derived from pepsinogen. In some embodiments, the amount of recombinant pepsinogen in the composition comprising recombinant pepsin is less than about 10%, 5%, 1%, 0.5%, 0.1% or 0.05% (weight pepsinogen/weight pepsin).
In some embodiments, active recombinant pepsin is then converted to stable (e.g., inactive) recombinant pepsin, such as by raising the pH. In some embodiments, a second pH shift step raises the pH to at least has a pH 5.4, e.g., about pH 6 or above pH 6, following the first pH shift step to maintain pepsin in a stable form that is enzymatically inactive when held at such pH conditions.
Raising the pH of a pepsin composition to greater than 5.4, e.g., about pH 6.0, obtains a stable recombinant pepsin composition. By stable is meant, in part, that the recombinant pepsin does not substantially digest itself and remains in an intact form. The compositions of the present disclosure comprise recombinant pepsins that are intact and in a stable proteolytically inactive form. This form is not present in natural pepsin because natural pepsin compositions self-digest over time (i.e., they are not stable in maintaining a substantially intact form of pepsin in the composition). Such an intact and stable proteolytically inactive form of the recombinant pepsin compositions provided herein advantageously allows long-term storage (at room temperature or at refrigeration temperature) of compositions of the present disclosure. Long-term storage may be for a month, two months, three months, four months, five months, six months, seven months, eight months, nine months, ten months, eleven months, twelve months or longer. After such long-term storage, the recombinant pepsin can be activated by lowering the pH of a composition. Enzymic activity of the re-activated recombinant pepsin is maintained after long-term storage, e.g., within about 15% of a composition's original activity.
In some embodiments, following the pH shift steps, the stable recombinant pepsin can be purified. For example, by removing contaminating proteins, carbohydrates, lipids, salts, nucleic acids, and small molecules.
In some embodiments, following the pH shift steps, the stable pepsin can be concentrated, such as to a 2×, 3×, 4×, 5×, 10× or greater than 10× concentrated form. In some embodiments, the concentrate is maintained as a liquid. In some embodiments, the concentrate is lyophilized or dried and stored as a solid or powder. In some embodiments, the stable pepsin concentrate can be diluted for formulation, for final product production or for consumption. In some embodiments, the diluted stable pepsin is maintained at a pH to about pH 6 or above pH 6. In some embodiments, the diluent for the pepsinogen composition is NaCl.
In some embodiments, stable recombinant pepsin is subsequently converted to an enzymatically active form, such as by lowering the pH (“activated recombinant pepsin composition”). Activated recombinant pepsin compositions provided herein can have a high specific activity.
In some embodiments, the method further comprises a step of isolating the activated pepsin polypeptide from contaminating proteins, carbohydrates, lipids, salts, nucleic acids, and small molecules in the liquid starting material and the lowering of the pH of the liquid starting material may be performed after the isolating the recombinant pepsin polypeptide to provide an activated recombinant pepsin composition. In some embodiments, the isolating of the activated pepsin polypeptide occurs after a step of lowering the pH of the liquid starting material to less than pH 4.0 to obtain an activated pepsin composition and a step of raising the activated pepsin composition to a pH of about 6.0 to obtain a high-activity stable pepsin composition.
For example, a stable and inactive recombinant pepsin composition, which has a pH of about 6, can be converted into an active recombinant pepsin composition by lowering the pH of the composition to less than pH 4.0.
Compositions and Uses of Compositions
Recombinant pepsin compositions can include stable recombinant pepsin, a concentrate of stable recombinant pepsin, a dilution of stable recombinant pepsin, as well as mixtures of stable recombinant pepsin with one or more additional ingredients. Recombinant pepsin compositions of the present disclosure may include additional proteins, e.g., proteins added to promote desirable qualities and features to a composition.
In some embodiments, a composition comprising recombinant pepsin is substantially free from animal-derived proteins.
Recombinant pepsin compositions also can include activated recombinant pepsin compositions, a dilution of activated recombinant pepsin compositions, as well as mixtures of activated recombinant pepsin compositions with one or more additional ingredients. Recombinant pepsin compositions of the present disclosure may include additional proteins, e.g., proteins added to promote desirable qualities and features to a composition.
In some embodiments, the recombinant pepsin compositions are substantially free contaminating proteins, carbohydrates, lipids, salts, nucleic acids, and small molecules.
Recombinant pepsinogen compositions can include recombinant pepsinogen, a concentrate of recombinant pepsinogen, as well as mixtures of recombinant pepsinogen with one or more additional ingredients.
In some embodiments, the activated recombinant pepsin compositions disclosed herein (after the pH has been lowered) provide a specific activity that is higher than commercially-available pepsin-related products. In some embodiments, the activated recombinant pepsin composition provided herein have a specific activity that is at least about 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 75%, 80%, 90% or 100% higher than a commercially-available pepsin-related product. In some embodiments, the activated recombinant pepsin composition provided herein have a specific activity that is at least about 1.2, 1.5, 1.7, 2, 2.5, 3, 3.5 or greater than 3.5-fold higher than a commercially-available pepsin-related product.
In some embodiments, a recombinant pepsin composition, such as a recombinant pepsin composition comprising a pepsin polypeptide substantially in an intact and stable proteolytically inactive form, is in a powdered form of the composition. In some embodiments, a recombinant pepsin composition, such as a recombinant pepsin composition comprising a pepsin polypeptide substantially in an intact and stable proteolytically inactive form, is in a liquid form of the composition. The proteolytically inactive pepsin polypeptide form (in a powdered or a liquid composition) may be stable for at least six months at room temperature, e.g., six months, seven months, eight months, nine months, ten months, eleven months, twelve months or longer. The proteolytically inactive pepsin polypeptide form (in a powdered or a liquid composition) may be stable in the composition for at least six months at 4° C., e.g., six months, seven months, eight months, nine months, ten months, eleven months, twelve months or longer. A powdered composition may have a moisture content of less than about 10%, e.g., less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, or lower.
In some embodiments, a recombinant pepsin composition has a specific activity at pH of 2 of at least 30,000 FCC units/mg total protein (expressed as units of pepsin activity per total of all protein in the composition), e.g., of at least 35,000 FCC units/mg total protein, at least 40,000 FCC units/mg total protein, of at least 45,000 FCC units/mg total protein, at least 50,000 FCC units/mg total protein, of at least 55,000 FCC units/mg total protein, at least 60,000 FCC units/mg total protein, of at least 65,000 FCC units/mg total protein, and at least 70,000 FCC units/mg total protein. The FCC units/mg total protein may relate to the total amount of recombinant pepsin protein alone. As mentioned above, a recombinant pepsin compositions of the present disclosure may include additional proteins; thus, the FCC units/mg total protein may relate to the recombinant pepsin protein and the additional proteins.
In some embodiments, a powdered recombinant pepsin composition has a specific activity at pH of 2 of at least 30,000 FCC units/mg total powder, e.g., of at least 35,000 FCC units/mg total powder, at least 40,000 FCC units/mg total powder, at least 45,000 FCC units/mg total powder, at least 50,000 FCC units/mg total powder, at least 55,000 FCC units/mg total powder, at least 60,000 FCC units/mg total powder, at least 65,000 FCC units/mg total powder, and at least 70,000 FCC units/mg total powder. As used herein, an FCC unit (also referred to herein as a pepsin unit) is defined as that quantity of enzyme that produces the equivalent of 1 μmol of tyrosine per min under the conditions of incubating the enzyme with 2% hemoglobin substrate at pH 1.6 for 10 minutes at 25° C. (see Food Chemical Codex, 11th ed. (Pharmacopeial Convention. 2018) at 1386-87 “Pepsin Activity”).
In some embodiments, the recombinant pepsinogen compositions disclosed herein, have a significantly lower amount of pepsin in the composition initially, e.g., such as when secreted from a host cell, as compared to commercially-available pepsin-related products. In some embodiments, the amount of recombinant pepsin in the recombinant pepsinogen compositions disclosed herein is less than 50%, 25%, 10%, 5%, 1%, 0.1% or less than 0.1% of the pepsin found in commercially-available pepsin-related products.
A consumable composition can be an ingredient of a final product or finished product. For example, recombinant pepsinogen or recombinant pepsin can be mixed with water or other liquids to form a proteolytically inactive solution of recombinant pepsinogen or recombinant pepsin. In some cases, recombinant pepsinogen or recombinant pepsin can be mixed with water or other liquids to form a proteolytically active solution of recombinant pepsin. This solution can be an ingredient that is then mixed with other ingredients to make a final product for an end-user. A final or finished product is one that is ready for an end-user's use, such as for use in a food-making or industrial process, or for use as a digestive aid or treatment by an end-user for consumption by an animal, such as a human, companion animal or livestock. The finished product can be a processed product, such as processed food or a processed drink, or an industrial product, such as preparation of proteins, antibodies and peptides for use in medicine and in uses such as hide and leather preparation. In some instances, the pepsinogen or pepsin is provided in a separate container to be mixed into the final product or with other components to make a final product by the end-user.
In some embodiments, the recombinant pepsinogen compositions and recombinant pepsin compositions provided herein are formulated. Formulation can include ingredients suitable to create an orally consumable ingredient or orally administered pharmaceutical formulation. A formulated comprising recombinant pepsinogen or recombinant pepsin may comprise at least 2 g, 5 g, 7 g, 10 g, 15 g, 20 g of the enzyme per liter of the composition.
In some embodiments, the recombinant pepsin polypeptide in a composition comprises SEQ ID NO: 10, or an amino acid sequence with at least 90% identity thereto.
In some embodiments, a recombinant pepsinogen or recombinant pepsin compositions disclosed herein are formulated as a digestive aid, such as in a pill, powder, tablet, capsule, caplets, liquid, syrup, gel or other suitable forms for human and animal oral ingestion. A recombinant pepsinogen composition or a recombinant pepsin composition may be formulated as a microencapsulate or liposomes suspended in syrups, liquids, sugar and pectin-based confectionary. Digestive aid recombinant pepsinogen or recombinant pepsin compositions can be ingested by an animal, including but not limited to human, companion animal or farm animal, to provide pepsin to aid the animal's digestion. For example, such digestive aid recombinant pepsin composition can be taken orally with the form of the enzyme in the composition as primarily or substantially the inactive pepsin form. Upon reaching an acidic environment in the animal's gut, the pepsin is converted into the active enzymatic form of pepsin and then the recombinant pepsin can aid in breaking down other proteins in the animal's gut to aid in the animal's digestion and improve nutrient absorption.
A recombinant pepsinogen composition or a recombinant pepsin composition may also be formulated for the treatment of disease or condition of the gastrointestinal tract. For instance, a recombinant pepsin composition may be administered to a subject with a disease or condition of the gastrointestinal tract; here, the recombinant pepsin is in a primarily or substantially inactive form. The recombinant pepsin composition may then be activated in the subject's gastrointestinal tract and release the active form of the pepsin enzyme. A subject can be an animal, such as a human, a companion animal or livestock animal.
In some embodiments, a digestive aid recombinant pepsin composition is mixed with an ingredient, such as lactose, to modify its enzymatic activity.
In some embodiments, the recombinant pepsinogen or recombinant pepsin compositions disclosed herein are useful for preparation of biological tools and therapeutics. For example, the recombinant pepsinogen or recombinant pepsin compositions can be converted to composition containing active pepsin and employed to create antibody fragments, such as Fabs, that can be used for diagnostic and therapeutic applications, as well as used as tools in biotechnology.
In some embodiments, the recombinant pepsinogen or recombinant pepsin compositions disclosed herein are used for preparation of food, beverage and other consumable compositions, such as for products that have soy or gelatin as ingredients. Recombinant pepsinogen or recombinant pepsin compositions disclosed herein can be used for making animal and vegetable protein hydrolysates for use in flavoring foods and beverages, and for making snack items and instant hot cereals. Exemplary uses include but are not limited to ale, beer, light beer, malt liquor, porter, stout, cheese (such as cheddar, cottage cheese, cream cheese, cream cheese spread), defatted soya flour, pre-cooked instant breakfast cereals, and hydrolyzed animal, milk and vegetable proteins. Recombinant pepsinogen or recombinant pepsin compositions also have utility in treating allergen-causing food items, such as legumes, to reduce allergic reactions when consumed by an animal, such as for human consumption.
The recombinant pepsinogen or recombinant pepsin compositions disclosed herein can used to make animal-free products and ingredients, such as animal free pharmaceuticals, digestive aids, food and beverage ingredients, food and beverage products and enzyme preparations (such as animal-free rennet for use in cheese-making.
The recombinant pepsinogen or recombinant pepsin compositions disclosed herein can used for vegetarian, vegan, kosher and halal ingredients and products.
Embodiment 1: A composition comprising a recombinant pepsinogen polypeptide, wherein the pepsinogen is substantially in a stable proteolytically inactive form.
Embodiment 2: The composition of embodiment 1, wherein the pepsinogen polypeptide is present in at least 5 g per liter in the composition.
Embodiment 3: The composition of embodiment 1 or embodiment 2, wherein the pepsinogen polypeptide when converted to a proteolytically active form has a higher specific activity as compared to native bovine pepsin isolated from bovine stomach or native porcine pepsin isolated from porcine stomach in the same quantity.
Embodiment 4: The composition of embodiment 3, wherein the specific activity of the proteolytically active form is at least 2 times, 2.5 times or 3 times greater than the native bovine pepsin or native porcine pepsin.
Embodiment 5: The composition of embodiment 1 or embodiment 2, wherein the pepsinogen polypeptide is converted to a proteolytically active form and the proteolytically active form has a specific activity of at least 50000 or 60000 or 70000 FCC units/mg protein.
Embodiment 6: The composition according to any of embodiments 1 to 5, wherein the recombinant pepsinogen polypeptide is produced in a yeast or filamentous fungi, a Saccharomyces species, a bacteria, a Pichia species, a Trichoderma species or an Aspergillus species.
Embodiment 7: The composition of embodiment 6, wherein the recombinant pepsinogen polypeptide is produced in a Pichia species.
Embodiment 8: The composition of embodiment 1, wherein the pepsinogen exhibits stability in the inactive form for at least 6 months.
Embodiment 9: The composition according to any of embodiments 1 to 8, wherein the composition is in powder form.
Embodiment 10: The composition according to any of embodiments 1 to 9, wherein the recombinant pepsinogen polypeptide is a porcine, bovine, ovine, equine or human pepsinogen.
Embodiment 11: The composition according to any of embodiments 1 to 9, wherein the recombinant pepsinogen polypeptide comprises an amino acid sequence of any one of SEQ ID NOs: 1-9, or an amino acid sequence having at least 80% homology with any one of SEQ ID NOs: 1-9.
Embodiment 12: A method of obtaining high quantities of recombinant pepsinogen in an inactive form comprising: providing a host cell comprising a nucleic acid encoding a pepsinogen polypeptide, wherein the nucleic acid further includes a segment directing secretion of the pepsinogen polypeptide from the cell; growing the host cell in a liquid medium, such that the pepsinogen polypeptide is expressed and secreted from the host cell under conditions whereby the pepsinogen polypeptide is substantially in a proteolytically inactive form; isolating liquid medium containing the secreted pepsinogen polypeptide.
Embodiment 13: The method of embodiment 12, wherein the host cell further comprises an inducible promoter driving the expression of the nucleic acid encoding the pepsinogen polypeptide.
Embodiment 14: The method of embodiment 2, wherein the method further comprises a step of inducing the expression of the pepsinogen subsequent to or at least partially concurrent with the growing step.
Embodiment 15: The method of embodiment 13 or embodiment 14, wherein the promoter driving the pepsinogen expression is induced by methanol.
Embodiment 16: The method according to any of embodiments 12-15, further comprising treating the isolated liquid media to adjust the pH to about 2-4 followed by an adjustment of the pH to 5.5-7.0, e.g., pH 6.
Embodiment 17: The method of embodiment 16, wherein the isolated liquid media is filtered at one or more points selected from the group consisting of (i) prior to adjusting the pH to 3.5, (ii) after adjusting the pH to 6.0, (iii) after a desalting step; (iv) prior to lyophilization and (v) a combination of any of (i)-(iv).
Embodiment 18: The method of embodiment 12, wherein the pepsin polypeptide is present in at least about 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or greater than 20 g/liter in the liquid media.
Embodiment 19: The method according to any of embodiments 12-18, wherein the method further comprises the activation to an enzymatically active or mature form of the enzyme.
Embodiment 20: The method according to embodiment 19, wherein the pepsinogen polypeptide when converted to an enzymatically active form has a higher specific activity as compared to native bovine pepsin isolated from bovine stomach or native porcine pepsin isolated from porcine stomach in the same quantity.
Embodiment 21: The method of embodiment 19, wherein the specific activity of the enzymatically active form is at least 2 times, 2.5 times or 3 times greater than the native bovine pepsin or native porcine pepsin.
Embodiment 22: The method according to any of embodiments 12-20, wherein the pepsinogen polypeptide is converted to an enzymatically active form and the enzymatically active form has a specific activity of at least 50000 or 60000 or 70000 FCC units/mg protein.
Embodiment 23: The method according to any of embodiments 12-21, wherein the host cell is a yeast or filamentous fungi, a Saccharomyces species, a bacteria, a Pichia species, a Trichoderma species or an Aspergillus species.
Embodiment 24: The method of embodiment 22, wherein the host cell is a Pichia species.
Embodiment 25: The method according to any of embodiments 12-23, wherein the pepsinogen polypeptide exhibits stability in the inactive or immature form for at least 6 months.
Embodiment 26: The method according to any of embodiments 12-24, wherein the composition is in powder form.
Embodiment 27: The method according to any of embodiments 12-25, wherein the recombinant pepsinogen polypeptide is a porcine, bovine, ovine, equine or human pepsinogen.
Embodiment 28: The method according to any of embodiments 12-25, wherein the recombinant pepsinogen polypeptide comprises an amino acid sequence of any one of SEQ ID NOs: 1-9, or an amino acid sequence having at least 80% homology with any one of SEQ ID NOs: 1-9.
Embodiment 29: A formulated composition comprising a recombinant pepsinogen and at least one formulated ingredient, wherein the formulated composition is in a form selected from the group consisting of a powder, a pill, a tablet and a capsule, a microencapsulate, a liposome suspended in syrup and wherein the pepsinogen is substantially enzymatically inactive.
Embodiment 30: The composition of embodiment 28, wherein the formulated composition is substantially devoid of pepsin.
Embodiment 31: The composition of embodiment 29, wherein the amount of pepsin is less than 10%, 5%, 1%, 0.5%, 0.1% or 0.05% (weight pepsin/weight pepsinogen).
Embodiment 32: The composition of embodiment 28, wherein the pepsinogen is capable of activation when exposed to a pH less than about 6.
Embodiment 33: The formulated composition of embodiment 31, wherein the pH of the composition is greater than about 6.
Embodiment 34: The formulated composition of embodiment 31, wherein the pepsinogen is capable of activation when exposed to an animal gut environment.
Embodiment 35: The formulated composition of embodiment 28, wherein the recombinant pepsinogen is a bovine, porcine, ovine or human enzyme.
Embodiment 36: A method of preparing a formulated pepsinogen composition comprising: providing a recombinant pepsinogen, wherein the pepsinogen is substantially enzymatically inactive; formulating the recombinant pepsinogen with at least one ingredient to create a formulated pepsinogen composition in powder, pill, tablet or capsule form: wherein the formulated pepsinogen composition is capable of activation when exposed to a pH of less than about 6.
Embodiment 37: The method of embodiment 35, wherein the recombinant pepsinogen is a bovine, porcine, ovine or human enzyme.
Embodiment 38: The method of embodiment 35, wherein the recombinant pepsinogen is produced in a heterologous host cell selected from the group consisting of bacteria, yeast, and filamentous fungi.
Embodiment 39: The method of embodiment 35, wherein the host cell is a Pichia species, a Saccharomyces species, a bacteria, an Aspergillus or a Trichoderma species.
Embodiment 40: The method of embodiment 36-39, wherein the recombinant pepsinogen is secreted from the host cell.
Embodiment 41: The method of embodiment 40, wherein the recombinant pepsinogen secreted is in a substantially enzymatically inactive form.
Embodiment 42: A composition comprising recombinant stable pepsin, wherein the stable pepsin is substantially enzymatically inactive.
Embodiment 43: The composition of embodiment 42, wherein recombinant stable pepsin is capable of activation when exposed to a pH less than about 6.
Embodiment 44: The composition of embodiment 42, wherein the pH of the composition is greater than about 6.
Embodiment 45: The composition of embodiment 42, wherein the recombinant stable pepsin is capable of activation when exposed to an animal gut environment.
Embodiment 46: The composition of embodiment 42, wherein the recombinant stable pepsin is a bovine, porcine, ovine or human enzyme.
Embodiment 47: The composition according to any of embodiments 42-46, wherein the specific activity of the recombinant stable pepsin when activated to a proteolytically active form is at least 2 times, 2.5 times or 3 times greater than the native bovine pepsin or native porcine pepsin.
Embodiment 48: The composition according to any of embodiments 42-46, wherein the recombinant stable pepsin when converted to a proteolytically active form has a specific activity of at least 50000 or 60000 or 70000 FCC units/mg protein.
Embodiment 49: The composition according to any of embodiments 42-48, wherein the recombinant stable pepsin is first produced as a pepsinogen polypeptide in a yeast or filamentous fungi, a Saccharomyces species, a bacteria, a Pichia species, a Trichoderma species or an Aspergillus species and then converted to pepsin.
Embodiment 50: A method of treating a disease or condition of the gastrointestinal tract comprising: providing a recombinant pepsinogen in a formulated composition, wherein the pepsinogen is substantially enzymatically inactive in the formulated composition; administering the formulated composition for oral administration; wherein upon contact of the formulated composition with an animal gut environment, the pepsinogen is converted to an enzymatically active form; and wherein the enzymatically active form is effective to treat the disease or condition of the gastrointestinal tract.
Embodiment 51: The composition of any of embodiments 1-11, wherein the composition comprises at least one production specification set forth in Table 2.
Embodiment 52: The composition of any of embodiments 1-11 or embodiment 51, wherein the composition comprises at least one quality specification set forth in Table 3.
The coding sequence of porcine pepsinogen (SEQ ID NO: 2) was fused to the Saccharomyces alpha factor pre-pro secretion signal under the control of a methanol-induced promoter. The fusion was constructed such that the pro form, pepsinogen, lacking the native secretion signal was produced upon expression and secretion of the pepsinogen.
The P. pastoris strain BG08 (BioGrammatics Inc., Carlsbad; CA, USA) is a single colony isolate from the Phillips Petroleum strain NRRL Y-11430 obtained from the Agriculture Research Service culture collection (Sturmberger, et al. 2016). P. pastoris BG10 (BioGrammatics Inc, Carlsbad, Calif., USA) was derived from BG08 using Hoechst dye selection to remove cytoplasmic killer plasmids (Sturmberger, et al. 2016). This BG10 strain was then further modified to have a deletion in the Alcohol Oxidase 1 gene (AOX1). This deletion generates a methanol-utilization slow (mutS) phenotype that reduces the strain's ability to consume methanol. This base strain was called DFB-001 and used for the transformation of the pepsinogen construct.
The pepsinogen construct, along with a construct for the expression of the P. pastoris transcription factor HAC1 under the control of a strong methanol inducible promoter, was transformed into Pichia pastoris and isolates were selected that expressed and secreted pepsinogen. A transformant was selected as a high-producer for use in subsequent steps. Propagation of the strain confirmed that all changes introduced into the strain were stably integrated in the genome and confirmed to be present after >45 generations of growth on non-selective growth media.
Sequencing confirmed that this strain does not contain any antibiotic markers or prokaryotic vector origin of replication sequences.
The resulting strain was grown in fermentation conditions in high-density growth conditions at about pH 5. After about 36 hours of growth under fermentation conditions, the pH was raised to about pH 6, and expression of pepsinogen was induced by the addition of methanol to the culture. The pepsinogen was isolated from the growth media of the culture.
From the growth media from fermentation of Example 1, the liquid was centrifuged to remove cells. This was followed by filtration of the supernatant using a 0.2 um hollow fiber membrane filtration to remove host protein and cell debris.
The solution was then concentrated to a 5× to 10× concentrate using 10 kDa hollow fiber membrane filtration. An acid solution of 85% phosphoric acid was added to the resulting liquid composition from Example 1 to lower the pH to 3.5, and the mixture was agitated for 2.25 hours at room temperature (about 20-25° C.). Following this agitation step, the pH was raised to 6 by addition of 5 N NaOH. The resulting concentrate was desalted with 10 DV of distilled water at pH 6 using 10 kDa hollow fiber membrane filtration. Then the solution was lyophilized to produce a pepsin powder.
The pepsinogen composition (Example 2) was characterized for its activation post dilution, e.g., conversion to active pepsin, under various temperature and pH ranges. In
Lyophilized pepsin powder (Example 2) was subjected to a protein determination using combustion analysis (N×6.25) and activity was measured in an FCC9 enzyme assay (USP, Pepsin activity. In: Ninth Edition of the Food Chemicals Codex (FCC 9). United States Pharmacopeia Convention, Rockville, Md., 2015e, pp. 1410-1411; see also Food Chemical Codex, 11th ed. (Pharmacopeial Convention. 2018) at 1386-87 “Pepsin Activity”). As compared to a commercially-available porcine pepsin product, the recombinant pepsin composition had over 3-times the specific activity.
Table 1 shows the results of the analysis for protein, fat, moisture, ash, carbohydrates and FCC units for the commercially-available native porcine pepsin and for a composition comprising recombinant pepsin. FCC units/mg is defined as follows: One pepsin unit is defined as that quantity of enzyme that produces the equivalent of 1 μmol of tyrosine per min under the conditions of incubating the enzyme with a 2% hemoglobin substrate at pH 1.6 for 10 minutes at 25° C. performed as set forth in Food Chemical Codex, 11th ed. (Pharmacopeial Convention. 2018) at 1386-87 “Pepsin Activity” (the same assay is also provided in Ninth Edition of the Food Chemicals Codex (FCC 9). United States Pharmacopeia Convention, Rockville, Md., 2015e, pp. 1410-1411).
Surprisingly, while the percentage of protein in the recombinant pepsin composition is significantly lower than the commercially-available native pepsin, the FCC units of the recombinant pepsinogen composition is significantly (about 3×) higher. Without wishing to be bound by theory, the methods for manufacturing the pepsin compositions of the present disclosure provide a highly active product.
A recombinant pepsin composition was tested for activity against a range of pH and compared against the activity of native porcine pepsin (see Example 4) using the FCC (9th Edition) Pepsin assay (Pharmacopeial Convention. 2014). The optimum activity was at pH 2 for both porcine pepsin and the recombinant pepsin polypeptide of the present disclosure. Both pepsin enzymes tested had a similar activity profile (
In some cases, pepsin assays were performed with the following changes (“alternate pepsin assay”) to the assay described in Example 4: The activity assay was performed at 37° C. in a 96-well plate format and tyrosine was measured directly. These changes result in an output number that when multiplied by two (2) is equivalent to the FCC units of activity performed as in Example 4. The numbers reported for all alternate pepsin assays herein apply this conversion factor.
A recombinant pepsin composition and native porcine pepsin (see Example 4) were compared for immunoreactivity and molecular weight using western blotting technique (Tobin). Briefly, three separately generated lots of the recombinant pepsin composition (PEP19232, PEP19241, PEP19252) and native porcine pepsin were run on SDS-PAGE and then transferred to nitrocellulose membrane. Western Blot was performed on the samples using primary pepsin antibody from rabbit (Abcam (ab182945)) at a 1:5000 dilution (Jensen 2012). The secondary antibody used was Goat anti-rabbit IgG conjugated to alkaline phosphatase (1:5000 dilution).
Based upon the characterization of the recombinant pepsin compositions and the properties of commercially-available native pepsin, product specifications (Table 2) and quality control specifications (Table 3) were constructed.
Salmonella
E. coli
1Food Chemical Codex, 9th ed. (Pharmacopeial Convention. 2014)
2Association of Official Analytical Chemists (1995). In Official Methods of Analysis.
3J AOAC Int. 2012 September-October; 95(5): 1392-7.
4J. AOAC vol. 90 (2007) 844-856.
5AOAC International (2005). Aerobic plate count in foods, dry rehydratable film, method 990.12. AOAC International, 17th ed. Gaithersburg, MD.
617.2.09 AOAC Official Method 997.02. Yeast and Mold Counts in Foods Dry Rehydratable Film Method (Petrifilm ™ Method) First Action 1997 Final Action 2000
7AOAC International. 2005. Salmonella in selected foods, BAX automated system, method 2003.09. In Official methods of analysis of AOAC International, 17th ed. AOAC International, Gaithersburg, MD.
8AOAC International. 2005, E. coli count, in foods, dry rehydratable film, method 991.14. in Official methods of analysis of AOAC international, 17th ed. AOAC International, Gaithersburg, MD.
Salmonella
E. coli
In this example, experiments were performed to confirm the absence of transformable DNA in the recombinant pepsin preparation made and isolated from the Pichia strain.
Materials: 2× Taq MasterMix from NEB; Primers: 5′GAAGCTGAAGCTCTAGTAAAGGTGCCTCTAG (forward; SEQ ID NO: 12); 5′ TGCAACAGGTGCTAGACCCACCTTGTTGTTAG (reverse; SEQ ID NO: 13). The primers have an annealing temp of 58° C. when using 2× Taq MasterMix); control DNA is the pepsinogen transformation cassette (Example 1).
Methods: A pepsin composition in powder form (see above Examples) was diluted to 100 mg powder/mL in 25 mM sodium hydroxide and then 250 μL was transferred to two new tubes with 250 μL of 25 mM sodium hydroxide (this created two new 500 μL tubes of 50 mg/mL pepsin). To one of these tubes, a positive control pepsinogen plasmid DNA was added to get a final concentration of 1 ng/μL (this served as a positive control for the assay). This tube was then used in sequential dilutions to generate a series of controls with the lowest concentration at 1 fg of control DNA. PCR reactions using the forward and reverse primers (of SEQ ID NOs: 12 and 13) were then performed on the powdered pepsin composition (without control DNA) and the series containing powdered pepsin compositions (with control DNA). PCR products were run on a 1% agarose gel. PCR product for pepsin (as shown in the control lanes) produced a 1122 bp band. This band was absent in each of the three powdered pepsin composition lots tested (see
Materials: Minimal methanol (MM) agar plates; Potato Glucose Agar (PGA) plates Procedure: Powdered recombinant pepsin compositions were plated on PGA plates. If samples yielded colonies, partial samples of the colony were streaked onto PGA plates and MM plates and incubated as follows: PGA plates for 48 hours at 30° C.; MM plates for 120 hours at 30° C. If colonies grew on MM plates within 120 hours at 30° C., single colonies were picked and colony PCR with cassette specific primers was run. (see PCR method, Example 8). If colony PCR confirmed the presence of the pepsinogen expression cassette, it could be concluded that recombinant Pichia cells are present in the pepsin composition.
This procedure was applied to three lots of powdered pepsin composition produced from the recombinant strain (Example 1). No recombinant Pichia cells were detected in any of the lots (see Table 3 “source organism” set forth in Example 7).
A recombinant pepsin composition was compared to native porcine Pepsin A by liquid chromatography tandem mass spectrometry (LC-MS/MS). The protein samples were first digested into peptides using endoproteinase GluC or chymotrypsin, in parallel, to get improved cleavage of Pepsin A. The peptides produced were analyzed through LC-MS/MS. The resulting spectra were matched to peptide sequences using the software tool, X!tandem (see the World Wide Web at: proteomics.ucdavis.edu/protein-identification/). The results from the chymotrypsin digest are presented in Table 5. A summary of the proteins present by category is shown in Table 4.
The LC-MS/MS data for the recombinant pepsin exactly matched the mature form of native Sus scrofa (Porcine) Pepsin A (PEPA_PIG; SEQ ID NO 10).
Based on the LC-MS/MS results, recombinant pepsin (“rPepsin”) was found to contain an abundance of the PEPA_PIG porcine pepsin sequence (Table 4,
The native porcine pepsin contained PEPA_PIG sequence and other porcine proteins in high abundance whereas the recombinant pepsin compositions did not have as many protein impurities (Table 5).
taurus PE = 1 SV = 1 (CTRA_BOVIN)
phaffii (strain GS115/ATCC 20864)
scrofa OX = 9823 GN = SERPINF2 PE = 1
Without wishing to be bound by theory, the methods for manufacturing the pepsin compositions of the present disclosure provide a highly active product which is free from animal-derived proteins, and with low (or no detectable) amounts of host cell proteins.
The objective of this analysis was to determine the stability of a powdered recombinant composition. Here, a composition was diluted with common salt, under room temperature and refrigerated storage conditions.
Material and Methods:
Sample preparation: a powdered recombinant pepsin composition (Lot # PEP19225) was diluted with sodium chloride (Micro powder salt flour, The Great American Spice Company) to achieve an activity of 10000 FCC Units/mg powder. After thorough mixing, the diluted composition was aliquoted into 25 Kraft barrier pouches (FDA and USDA compliant) and sealed.
One pouch was sent for analysis for baseline data (Time Point TP 0). Twelve pouches were stored at about 4° C. and another twelve were stored at room temperature. Samples were pulled from each of the two storage conditions at monthly intervals and sent for analyses.
Tests conducted:
Results for the first seven months of the room temperature (18° C. to 20° C.) study are shown below in Table 6 and results for the first five months of the refrigerated (˜4° C.) study are shown below in Table 7.
These data show that the microbial load on the samples over the first seven months was well within acceptable limits for both refrigerated and room temperature storage conditions. The recombinant pepsin activity was stable for at least seven months under refrigerated storage and at room temperature.
Without wishing to be bound by theory, the methods for manufacturing the powdered pepsin compositions of the present disclosure provide a highly stable product.
The objective of this analysis was to determine the stability of a liquid recombinant composition. Here, a composition was diluted with phosphate citrate buffer, under refrigerated storage conditions over a period of time.
Material and Methods:
A powdered recombinant pepsin composition (GRAS Test Lot #2 (CS462) was obtained and diluted in 0.01 M phosphate citrate buffer, pH 6.0, to produce a composition comprising 1% recombinant pepsin. The composition was aliquoted into 50 ml conical tube and stored in a 4° C. refrigerator.
Samples were collected every two weeks and pepsin activity was assayed; using an assay based on the Worthington Pepsin Assay: hemoglobin substrate, pH 1.6, 37 C, 10 minutes.
Data is shown below in Table 8 and
These data show that the liquid recombinant pepsin composition had maintained activity within the variation of the pepsin activity assay (15%) over the course of 46 days at 4° C. Thus, the recombinant pepsin composition can be considered liquid-stable at pH 6.
Without wishing to be bound by theory, the methods for manufacturing the liquid pepsin compositions of the present disclosure provide a highly stable product.
While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.
This application claims the benefit of U.S. Provisional Application No. 62/883,800, filed Aug. 7, 2019 and U.S. Provisional Application No. 62/941,627, filed Nov. 27, 2019. The contents of each of which in incorporated by reference in its entirety.
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| 3251697 | Hans et al. | May 1966 | A |
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| 62941627 | Nov 2019 | US |
