Non-steroidal suicide substrates of hydroxysteroid dehydrogenase

Abstract

Compounds, such as 1-(4'-nitrophenyl)-2-propen-1-ol, are disclosed which are highly selective non-steroidal suicide substrates for rat liver 3.alpha.-hydroxysteroid dehydrogenase.

Description

This invention relates to non-steroidal compounds which function as highly selective suicide substrates for the enzyme 3-hydroxysteroid dehydrogenase (EC 1.1.1.50; 3.alpha.-HSD).

Hydroxysteroid dehydrogenases (HSD's) are a family of enzymes which play a pivotal role in the regulation of steroid hormone action. These enzymes catalyze the interconversion of secondary alcohols to ketones in a positional and stereospecific manner on the steroid nucleus and side chain. They require nicotinamide dinucleotide (phosphate) NAD(P)+ as cofactor. For example, 3.alpha.-HSD catalyzes the reduction 5.alpha.-dihydrotestosterone (a potent androgenic steroid hormone) to 5.alpha.-androstan-3.alpha.,17.beta.-diol (a non-androgen). In this reaction a 3-ketosteroid is converted to a 3.alpha.-hydroxysteroid and as a result the potency of the steroid hormone is decreased by five-orders of magnitude. Other HSD's carry out reactions of similar importance in the regulation of estrogen and progestin action. As a family HSD's represent target enzymes for drug development.

Research groups headed by Dr. Cecil H. Robinson (Johns Hopkins University) and by Dr. Douglas F. Covey (Washington University School of Medicine) have concentrated on the development of steroidal suicide substrates for these enzymes [BBRC, Vol. 101, No. 2, pp. 495-501 (1981); Steroids, vol. 40, No. 1 pp. 109-119 (1982); Steroids, vol. 34, No. 2 pp. 199-206 (1979); Biochemistry, vol. 25, No. 23, pp. 7295-7300 (1986)]. Suicide substrates mimic the normal substrate and are transformed by the enzyme's catalytic mechanism to highly reactive alkylating agents which then inactivate the enzyme by forming a covalent bond at the active site. In this manner the enzyme catalyzes its own destruction. These compounds have the potential to be highly selective since they are innocuous by themselves until they are transformed by the target enzyme.

Based on the known function of 3.alpha.-HSD, suicide substrates for this enzyme may have a therapeutic use in potentiating the action of androgens and could be used as an adjuvant in androgen replacement therapy. Such therapy is routinely used in the treatment of hypogonadism of pituitary and testicular origin. Androgens are also essential for the maintenance of male fertility, they are anabolic and can act as anti-estrogens.

3.alpha.-HSD and several other hydroxysteroid dehydrogenases have been reported to catalyze the oxido-reduction of non-steroidal substrates. Examples include 3.beta.-HSD from Pseudomonas testosteroni which reduces cyclohexanone as well as bicyclic and tricyclic ketones [Prog. in Hormone Res. vol. 23, pp. 349-373 (1967)], 3.alpha.-HSD and 17.beta.-HSD from rat and mouse liver respectively, which oxidize 1,2-trans-dihydroxy-3,5-cyclohexadiene [Biochem. J., vol. 222, No. 3, pp. 601-611 (1984); J. Biol. Chem., vol. 258, No. 12., pp. 7252-7255 (1983)], and rat liver 3.alpha.-HSD which reduces aromatic ketones and quinones [Biochem. J., vol. 222, No. 3, pp. 601-611 984)]. These observations suggest that suicide substrates based on non-steroids could provide an alternative rational approach to inhibitor design. In this invention monocyclic-aromatic allylic and acetylenic alcohols are shown to be highly selective suicide substrates of 3.alpha.-HSD. The non-steroidal nature of these compounds coupled with the fact they are less expensive and more readily synthesized indicate that they offer distinct advantages over their steroidal counterparts. This approach may be generally applicable for the development of suicide substrates for other HSD's.

Suicide substrates based on monocyclic-aromatic allylic and acetylenic alcohols covered by this invention are transformed by 3.alpha.-HSD to monocyclic-aromatic vinyl and acetylenic ketones. These ketones appear to have the unusual property of alkylating the pyridine nucleotide binding site of 3.alpha.-HSD. Monocyclic-aromatic vinyl and acetylenic ketones may represent a general class of affinity ligands for pyridine nucleotide binding sites.

A number of additional properties have been assigned to the purified 3.alpha.-HSD of rat liver cytosol which suggest that suicide substrates for this enzyme may have broader applications. For example, the enzyme can function as a hydroxyprostaglandin dehydrogenase and catalyze the conversion of PGF.sub.2.alpha. (a non-inflammatory prostaglandin) to PGE.sub.2 (a pro-inflammatory prostaglandin) [BBRC, vol. 148, No. 2, pp. 646-652 (1987)]. The enzyme is also potently inhibited in a competitive fashion by all the major classes of non-steroidal anti-inflammatory drugs, (NSAID's) in rank-order of their therapeutic potency. This inhibition occurs at concentrations that are beneath the peak plasma concentrations observed in man PNAS, vol. 80, No. 14, pp. 4504-4508 (1983)]. The anti-inflammatory drug sensitive 3.alpha.-HSD is widely distributed in rat tissues. It is found in high levels in tissues which play a role in the metabolism of prostaglandins, which are mediators of inflammation, e.g. lung, heart, seminal vesicle and spleen [Biochem. Pharm., vol. 34, No. 6, pp 831-835 (1985)]. These data suggest that 3.alpha.-HSD may act as an alternative target for anti-inflammatory drug action.

Because 3.alpha.-HSD displays these additional properties, suicide substrates based on monocyclic-aromatic allylic and acetylenic alcohols have now been coupled with appropriate functionalities to imitate NSAID's. Once these alcohols are oxidized by 3.alpha.-HSD to the corresponding ketones they have the capacity to alkylate the NSAID binding site in preference to the NAD(P).sup.+ binding site of 3.alpha.-HSD. This invention also covers these coupled compounds.

Based upon the known functions of 3.alpha.-HSD, suicide substrates for this enzyme may have the following broad uses: 1) They may potentiate androgen action and act as adjuvants in androgen therapy. 2) They may represent a new class of anti-inflammatory drugs, and 3) they may represent general suicide substrates of prostaglandin dehydrogenases.

SUMMARY OF THE INVENTION

Tests by the inventors indicate that 1-(4'-nitrophenyl)-2-propen-1-ol (I) and 1-(4'-nitrophenyl)-2-propyn-1-ol (II): ##STR1## are highly selective mechanism based inactivators of the enzyme 3.alpha.-HSD. They are oxidized by the dehydrogenase to the corresponding, -unsaturated ketones: 1-(4'-nitrophenyl)-2-propen-1-one (III) and 1-(4'-nitrophenyl)-2-propyn-1-one (IV).

These ketones subsequently inactivate the enzyme by a Michael addition as shown in scheme 1 for 1-(4'-nitrophenyl)-2-propen-1-ol: ##STR2##

The ketones, (III and IV), are stoichiometric inactivators of the dehydrogenase and can be used to titrate the purified enzyme. Current evidence indicates that the pyridine nucleotide binding domain may be labeled by the enzyme generated ketones in preference to the steroid binding site.

By converting the .alpha.,.beta.-unsaturated alcohols to analogs that imitate NSAID's; e.g. N-phenyl-anthranilic acids (V), 1-methyl-pyrrole acetic acids (VI) or aryl propionic acids (VII), (examples are shown in scheme 2), the resulting compounds have the potential to act as NSAID based suicide substrates of the dehydrogenase, scheme 3. The enzyme generated ketones would be expected to alkylate the anti-inflammatory drug binding site. ##STR3##

This invention therefore relates to a method of inactivating an enzyme selected from hydroxysteroid dehydrogenases, prostaglandin dehydrogenases and anti-inflammatory drug binding enzymes comprising contacting said enzyme with a compound of the formula ##STR4## where

R.sub.1 is selected from the groups consisting of CH.dbd.CH.sub.2, CH.dbd.CH--OMe, CH.dbd.CH--OEt, C.tbd.CH, C.tbd.C--OMe, and C.tbd.C--OEt;

R.sub.2 is selected from the groups consisting of NO.sub.2, Z, CH.sub.2 Z, CHZ.sub.2, CZ.sub.3, COOH, NH.sub.2 and OH;

R.sub.3 and R.sub.4 are independently selected from the groups consisting of H, NO.sub.2, Z, CH.sub.2 Z, CHZ.sub.2, CZ.sub.3, COOH, NH.sub.2 and OH;

R.sub.5 is selected from the groups consisting of ##STR5##

and Z is a halogen atom.

This invention further relates to a method of inactivating an enzyme selected from hydroxysteroid hydrogenases, prostaglandin dehydrogenases and anti-inflammatory drug binding enzymes comprising contacting said enzyme with a compound of the formula ##STR6## where

R.sub.1 is selected from the groups consisting of CH.dbd.CH.sub.2, CH.dbd.CH--OMe, CH.dbd.CH--OEt, C.tbd.CH, C.tbd.C--OMe, and C.tbd.C--OEt;

R.sub.2 is selected from the groups consisting of NO.sub.2, Z, CH.sub.2 Z, CHZ.sub.2, CZ.sub.3, COOH, NH.sub.2 and OH;

R.sub.3 and R.sub.4 are independently selected from the groups consisting of H, NO.sub.2, Z, CH.sub.2 Z, CHZ.sub.2, CZ.sub.3, COOH, NH.sub.2 and OH;

R.sub.5 is selected from the groups consisting of ##STR7##

and Z is a halogen atom,

under conditions which allow said enzyme to catalyze the oxidation of said compound to the corresponding ketone.

Still further, this invention relates to novel compounds which may be used in the above-mentioned methods. These compounds have the formulas: ##STR8## where

A is --C(O)-- or --CH(OH)--;

R.sub.1 is selected from the groups consisting of CH.dbd.CH.sub.2, CH.dbd.CH--OMe, CH.dbd.CH--OEt, C.tbd.CH, C.tbd.C--OMe, and C.tbd.C--OEt;

R.sub.2 is selected from the groups consisting of NO.sub.2, Z, CH.sub.2 Z, CHZ.sub.2, CZ.sub.3, COOH, NH.sub.2 and OH;

R.sub.3 and R.sub.4 are independently selected from the groups consisting of H, NO.sub.2, Z, CH.sub.2 Z, CHZ.sub.2, CZ.sub.3, COOH, NH.sub.2 and OH;

R.sub.5 is selected from the groups consisting of ##STR9##

and Z is a halogen atom,

provided that, for compounds of formula (v), when R.sub.2 .dbd.NO.sub.2 and R.sub.3 and R.sub.4 .dbd.H, then A.dbd.--CH(OH)-- and R.sub.1 is other than C.tbd.CH.

Still further, this invention relates to pharmaceutical compositions comprising one of the compounds of formulas (i), (ii), (iii) and (iv) above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a HPLC chromatogram identifying the product of the enzyme catalyzed oxidation of 1-(4'-nitrophenyl)-2-propen-1-ol.

FIGS. 2a and 2b are plots showing the time dependent inactivation of 3.alpha.-HSD by 1-(4'-nitrophenyl)-2-propen-1-ol.

FIGS. 3a and 3b are plots showing the time dependent inactivation of 3.alpha.-HSD by 1-(4'-nitrophenyl)-2-propen-1-one.

DETAILED DESCRIPTION OF THE INVENTION

Studies show that the allylic alcohol 1-(4'-nitrophenyl)-2-propen-1-ol can be oxidized by 3.alpha.-HSD in the presence of NAD.sup.+ (Km=2.02 mM and Vmax=0.58 .mu.moles/min/mg), to yield the active Michael acceptor 1-(4'-nitrophenyl)-2-propen-1-one, which has been identified by HPLC (high performance liquid chromatography), FIG. 1.

Enzymatic oxidation of the allylic alcohol (I) by 3.alpha.-HSD in the presence of micromolar concentrations of NAD.sup.+ results in a time-dependent loss of 3.alpha.-HSD activity as seen in FIG. 2a. The presence of NAD.sup.+ is obligatory for the inactivation of 3.alpha.-HSD by the allylic alcohol. Analysis of this data by the method of Kitz and Wilson, [J. Biol. Chem., vol. 237, No. 10 pp. 3245-3249 (1962)], yields a Ki of 1.2 mM for the alcohol and a t.sub.1/2 life for the enzyme at a saturating allylic alcohol concentration of 8 seconds, FIG. 2b.

The enone (III), produces inactivation of 3.alpha.-HSD at a rate too fast to accurately measure under the conditions employed. Incubation of sub-stoichiometric quantities of enone (III), with purified 3.alpha.-HSD results in the titration of 3.alpha.-HSD activity, FIG. 3.

Comparison of the rate of allylic alcohol oxidation with that of enzyme inactivation suggests that 10 molecules or less of the allylic alcohol (I) are oxidized for every molecule of enzyme inactivated. This ratio, known as the partition ratio is formally defined as kcat/kinact; for 1-(4'-nitrophenyl)-2-propen-1-ol it is estimated to be equal to 4 which is close to the theoretical limit of 1.

The acetylenic alcohol, 1-(4'-nitrophenyl)-2-propyn-1-ol (II), is oxidized by the enzyme with a Km and Vmax of 750 mM and 0.3 mMoles/min/mg respectively to yield the acetylenic ketone. The acetylenic ketone, (IV), once formed is highly reactive. Evidence that the acetylenic ketone is the product of enzymatic oxidation was obtained by trapping the enzymatic oxidation product as stable monothioether adducts with 2-mercaptoethanol. The adducts trapped in the enzymatic reaction were then characterized by comparing their retention times to synthetic standards of monothioether adducts by HPLC. Like the enone (III), the acetylenic ketone (IV), inactivates 3.alpha.-HSD in a rapid and stoichiometric manner.

Irrespective of whether the allylic alcohol, acetylenic alcohol or their corresponding ketones are used to inactivate 3.alpha.--HSD, inactivation is accompanied by stable covalent bond formation between the enzyme and the inactivator. Thus enzyme activity does not return upon either gel filtration or extensive dialysis of the inactivated enzyme.

Three types of experimental evidence indicate that both the enone (III), and the acetylenic ketone (IV), alkylate the pyridine nucleotide binding domain, in preference to the steroid binding site of the enzyme. First, steady state kinetic measurements indicate that the enone (III), and the acetylenic ketone (IV), are competitive inhibitors of NAD.sup.+ binding, and non-competitive or mixed inhibitors of androsterone binding. Second, NAD.sup.+ can provide complete protection of 3.alpha.-HSD from inactivation by III and IV, where as androsterone, and other compounds which are competitive for the steroid binding site, only slow the rate of inactivation, but do not completely block this event. Third, chromatographic experiments using the immobilized nucleotide analog Cibacron Blue, indicate that both native enzyme and enzyme inactivated with the steroid affinity alkylator, 17.alpha.-bromoacetoxy-5.alpha.-androstan-17.beta.-ol-3-one, bind tightly to the immobilized nucleotide analog. By contrast, enzyme inactivated by either III or IV has no affinity for the immobilized nucleotide analogue. This experimental evidence implies that the alkylators III and IV covalently modify the nucleotide binding domain of 3.alpha.--HSD.

Although a number of HSD's oxido-reduce a variety of non-steroidal substrates, the non-steroidal suicide substrates covered by this invention appear to be highly selective agents for 3.alpha.-HSD. Results of a broad screen in which the allylic (I) and acetylenic alcohols II) were examined as suicide substrates of the following enzymes: 3.alpha.-HSD and 3.beta.-HSD (Pseudomonas testosteroni), 3.alpha.,20 -HSD (Streptomyces hydrogenas), 20.alpha.-HSD (rat ovary), 3.beta.-HSD (rat liver), alcohol dehydrogenase (yeast), lactate dehydrogenase (porcine heart) and 3.alpha.-HSD (rat liver), indicated that only rat liver 3.alpha.-HSD effectively oxidized the alcohols and was subsequently inactivated by the enzyme generated ketones.

PREPARATION OF THE COMPOUNDS

Latent Michael acceptors of the general formula iii may be synthesized directly from the corresponding benzaldehyde and vinyl or acetylene magnesium bromide, as shown in the scheme 4. Subsequent oxidation yields the active Michael acceptor of general formula i. ##STR10##

The synthesis of N-phenyl-anthranilic acid analogues incorporating the latent aromatic Michael acceptors described above may be undertaken by a number of routes. The two principal reactions used to synthesize N-phenyl-anthranilic acids are the Ullmann reaction (for thorough reviews: Acheson, "Acridines" in The Chemistry of the Heterocyclic Compounds (Interscience, New York, 1956); Albert, "The Acridines" (Edward-Arnold Co. London, 1951) and diphenyliodonium-2-carboxylate coupling [J. Org. Chem. vol. 45, No. 11, pp. 2127-2131 (1980)], both are shown schematically below. Because they are largely complimentary in the substitutions they allow, diverse functionalities can be incorporated into the N-phenyl-anthranilic acid nucleus, scheme 5. ##STR11##

The 1-methyl-pyrrole acetic acid and arylpropionic acid analogs may be prepared by analogous methods known in the art.

The preparation of the compounds of this invention will be further illustrated by the following examples.

EXAMPLE 1

Preparation of 1-(4'-Nitrophenyl)-2-propen-1-ol, (I) and 1-(4'-Nitrophenyl)-2-propen-1-one, (II).

p-Nitrobenzaldehyde (1 g , 6.6 mMoles) and 30 ml of dry tetrahydrofuran (THF) was stirred at 0.degree. C. in a septum sealed flask equipped with a pressure equalizing funnel. After purging with dry nitrogen, 7 ml of 1M vinyl magnesium bromide in THF was added dropwise under a nitrogen atmosphere. After addition of the Grignard reagent, the reaction was allowed to stir at room temperature for 30 min. The bulk of the THF was removed under vacuum and the reaction was quenched by pouring it into a slurry containing 200 ml of water, crushed ice and 100 ml of ether. The final pH of the slurry was adjusted to near neutral by dropwise addition of 2M sulfuric acid. The product was extracted with ether and the pooled extracts were washed twice with 30 ml of water and twice with 30 ml of saturated NaCl. Ether was removed under vacuum yielding a dense yellow oil which was chromatographed on preparative silica TLC plates using toluene : acetonitrile 10:1 v/v) as running solvent. Elution of the product from silica with methanol yielded 700 mg of semi-crystalline 1-(4'-nitrophenyl)2-propen-1-ol. Recrystallization from toluene and then ethanol gave needles of pure product. I.r.:(chloroform) (cm.sup.-1) --OH, 3600, 1040; intermolecular --OH, 3550-3320; aromatic, 1670, 858; --NO.sub.2, 1510, 1350, 872; --C.dbd.CH.sub.2, 3020, 2870, 990, 940. N.m.r.: .delta.(p.p.m.) ([.sup.2 H]chloroform), 2.2 (1H, broad s, --OH, D.sub.2 O exchangeable), 5.26 (1H, d, J.sub.2,3 cis 10.6 Hz, J.sub.3,3 gem 1 Hz, --C.dbd.CH.sub.2), 5.32 (1H, broad m, --CH.dbd.C), 5.42 (1H, d, J.sub.2,3 trans 17.2 Hz, J.sub.3,3 gem 1 Hz --C.dbd.CH.sub.2), 6.0 (1H, m, C--CH.dbd.C), 7.4 (2H, d, J 9 Hz, aromatic), 8.21 (2H, d, J 9 Hz, aromatic). U.v. maximum 272 nm, .epsilon.=10,500M.sup.-1 cm.sup.-1. Mp. 55.degree. C.

Oxidation of 1-(4'-nitrophenyl)-2-propen-1-ol (200 mg) to yield 1-(4'-nitrophenyl)-2-propen-1-one was conducted in 5 ml of acetone at room temperature by the dropwise addition of Jones reagent, (CrO.sub.3 /H.sub.2 SO.sub.4) with stirring. Addition of the reagent was continued until the reaction remained yellow for more than 5 min. Addition of 0.2 ml of methanol consumed the excess oxidant. The reaction was poured into 40 ml of water and neutralized with 1M NaOH. The product was extracted into toluene until completion and the pooled extracts were washed with saturated Na.sub.2 CO.sub.3 followed by saturated NaCl. Removal of the toluene under vacuum gave a semi-crystalline mass of 1-(4'-nitrophenyl)-2-propen-1-one. Recrystallization from toluene then ethanol gave pure needles of product. I.r.: (chloroform) (cm.sup.-1) C.dbd.O, 1670; C.dbd.CH.sub.2, 1002, 911; aromatic, 1016, 855; --NO.sub.2, 1520, 1350, 870. N.m.r.: .delta.(p.p.m.) ([2H]chloroform) 6.15 (1H, m), 6.6 (1H, m), 7.2 (1H, m), 8.1 (2H, d, J 8 Hz, aromatic), 8.3 (2H, d, J 8 Hz, aromatic). U.v. maximum 266 nm, .epsilon..sub.266 =17,700M.sup.31 1 cm.sup.-1 M.p. 89.degree.-90.degree. C.

EXAMPLE 2

Preparation of 1-(4'-Nitrophenyl)-2-Propyn-1-ol, (II) and 1-(4'-nitrophenyl)-2-propyn-1-one, (IV)

Synthesis of the acetylenic alcohol (II), and ketone (IV), can be accomplished by the general method outlined for the allylic alcohol (I), and the enone (II , by substituting acetylene magnesium bromide for vinyl magnesium bromide. Acetylenic alcohol (II) I.r.: (chloroform) (cm .sup.-1 ) --OH, 3590, 1040; intermolecular --OH, 3550-3350; --C.tbd.CH, 3300, 2125, aromatic 1590, 844; NO.sub.2, 1500, 1340, 852. U.v. maximum 269 nm in acetonitrile, .epsilon..sub.269 =10,400M.sup.-1 cm.sup.-1. N.m.r.: .delta.(p.p.m.) ([.sup.2 H]chloroform) 2.75 (1H, d, J 2 Hz, --CH--C.tbd.C--), 3.0 (1H, broad s, D.sub.2 O exchangeable, --COH--C.tbd.C), 5.6 (1H, d, J 2 Hz, --C.tbd.CH), 7.6 (2H, d, J 9 Hz, aromatic), 8.2 (2H, d, J 9 Hz, aromatic). M.p. 57.degree. C.

Acetylenic ketone (III): I.r.: (chloroform) (cm.sup.-1) C.dbd.O, 1660; --C.tbd.CCH, 3300, 2100; aromatic, 1605, 855; NO.sub.2, 1520, 1340, 870 . U.v. maximum 271 nm in acetonitrile, .epsilon..sub.271 =16,620M.sup.-1 cm.sup.-1. N.m.r.: p.p.m.) ([2H]chloroform) 3.58 (1H, s, --C.tbd.CH), 8.37 (4H, s, aromatic). M.p. 125.degree.-127.degree. C.

EXAMPLE 3

Preparation of 2'-Nitro-5'-(2-propen-1-ol)-anthranilic acid (V)

Oxidation of 3-fluoro-4-nitrotoluene by one of two routes affords the corresponding aldehyde. Then, as in example 1, addition of vinyl magnesium bromide will yield the corresponding allylic alcohol. Subsequent coupling with 2-amino-benzoic acid via an Ullmann reaction will yield the N-phenyl-anthranilic acid containing a latent Michael acceptor, scheme 6. ##STR12##

Synthesis of the active Michael acceptor, the last step above, can be accomplished by a number of mild oxidants including those described by D. Swern [Synthesis, vol. 139, pp. 165-185 (1981)], MnO.sub.2 [Synthesis, vol. 133, pp. 65-76 (1976)] or chromic anhydride in hexamethyl phosphoric triamide which is specific for allylic alcohols [Synthesis, vol. 133, pp. 394-398 (1976)].

FIGURE LEGENDS

FIG. 1 shows the identification of the enzyme catalyzed oxidation product of the allylic alcohol (I) by HPLC. Systems (1 ml) containing 1.43 .mu.g of enzyme, 2.3 mM NAD.sup.+ and I.3 mM allylic alcohol in 0.1M potassium phosphate buffer pH 7.0 with 4% acetonitrile as a co-solvent were incubated at 25.degree. C. until no further change in the absorbance at 340 nm was observed. Portions of the reaction mixture were chromatographed on a Waters C18 .mu.Bondapak column pre-calibrated with standards using 45% acetonitrile in water as the mobile phase. Retention times for the allylic alcohol (I) and enone (III) standards (panel a); chromatogram resulting from the incubation containing 1.43 .mu.g of enzyme and 1.3 mM allylic alcohol, omitting NAD.sup.+ (panel b); chromatogram resulting from the incubation containing 2.3 mM NAD.sup.+ and 1.3 mM allylic alcohol, omitting enzyme (panel c); chromatogram resulting from the incubation containing the complete system, 1.43 .mu.g of enzyme, 2.3 mM NAD.sup.+ and 1.3 mM allylic alcohol (panel d).

FIG. 2 shows the time dependent inactivation of 3.alpha.-HSD by the allylic alcohol (I), in the presence and absence of NAD.sup.+. 3.alpha.-HSD (24 .mu.M of purified enzyme) was incubated in systems (30 .mu.l) containing 1.2 mM NAD.sup.+, 10 mM potassium phosphate buffer pH 7.0, 1 mM EDTA and 5% acetonitrile as a co-solvent. Enzyme activity was followed over time by diluting an aliquot of the incubation mixture into a 1 ml assay containing: 2.3 mM NAD.sup.+ and 75 .mu.M androsterone in 0.1M potassium phosphate buffer pH 7.0, with 4% acetonitrile as a co-solvent. Initial rates were determined spectrophotometrically by measuring the rate of NADH formation at 340 nM. Because of the 100 fold or greater dilution of the enzyme into the assay, the initial rate measured is an indication of the enzyme activity remaining at that time. Semi-log plots of the amount of enzyme remaining vs. time are curvilinear (panel a). Initial rates of inactivation (k.sub.app's) were estimated by taking tangents to these curves. Data was replotted as 1k.sub.app vs 1allylic alcohol from which k.sub.inact (the rate constant for e inactivation) and Ki (the binding constant of the allylic alcohol) were determined, (panel b).

FIG. 3 shows time dependent inactivation of 3.alpha.-HSD by the enone (III). Inactivation of 3.alpha.-HSD 24 .mu.M) was conducted in incubations (60 .mu.l) of 10 mM potassium phosphate buffer pH 7.o containing 1 mM EDTA and 4% acetonitrile as a co-solvent. After initial enzyme activity was determined (see the legend of FIG. 2 for assay composition), the concentration of inactivator indicated ( =0 .mu.M, o=2.1 .mu.M, =4.9 .mu.M, .gradient.=10.0 .mu.M, =15.0 .mu.M, .quadrature.=24.0 .mu.M) was added and the sample incubated at 25.degree. C. Over time samples were withdrawn and diluted into the standard assay to determine the amount of enzyme activity remaining. A secondary plot of the amount of enzyme inactivated vs. the amount of inhibitor added provided the stoichiometry of inactivation when corrected for nonspecific loss of enzyme activity (panel b). The continuous line without points is a theoretical line for a stoichiometry of 1:1.

The data presented herein suggest that compounds of formulas (i), (ii), (iii) and (iv) could be used in pharmaceutical compositions useful as adjuvants in androgen therapy and as anti-inflammatory drugs. This invention, therefore, further relates to pharmaceutical compositions comprising one or more compounds of formulas (i), (ii), (iii) and (iv), or pharmaceutically acceptable pharmaceutically acceptable carriers or diluents. Suitable pharmaceutical carriers ar well known in the art and are described, for example, in Remington's Pharmaceutical Sciences, E. W. Martin, a standard reference text in this field. Pharmaceutically acceptable salts include, but are not limited to, salts of hydrochloric, hydrobromic, sulfuric, benzenesulphonic, acetic, fumaric, oxalic, malic and citric acids, as well as hydroxides of potassium and sodium.

Claims

1. A method of inactivating the enzyme 3.alpha.-hydroxysteroid dehydrogenase, comprising contacting said enzyme with a compound of the general formula: ##STR13##

2. The method of claim 1 where said compound is 1-(4'-nitrophenyl)-2-propen-1-one.

3. A method of inactivating the enzyme 3.alpha.-hydroxysteroid dehydrogenase, comprising contacting said enzyme with a compound of the general formula: ##STR14##

4. The method of claim 3 where said compound is 1-(4'-nitrophenyl)-2-propen-1-ol.