Mayer M, Neufeld B, Finci Z
Biochem Pharmacol. 1982 Sep 15;31(18):2989-92. doi: 10.1016/0006-2952(82)90274-x.
Proteolysis of 14C-labeled globin, as well as the hydrolysis of the specific substrate benzoyl tyrosine ethyl ester, by purified bovine chymotrypsin was found to be inhibited by several steroid hormones. The inhibition of chymotrypsin by the steroids was of a competitive nature, with Ki values of 9.9 x 10(-5) M for triamcinolone (9-fluoro-11 beta, 16 alpha, 17,21-tetrahydroxy-1,4-pregnadiene-3,20-dione), 1.6 x 10(-4) M for cortisol (11 beta, 17 alpha, 21-trihydroxypregn-4-ene-3,20-dione), 3.7 x 10(-4) M for testosterone (17 beta-hydroxy-4-androsten-3-one), 5.0 x 10(-4) M for dexamethasone (9-fluoro-11 beta, 17,21-trihydroxy-16 alpha-methyl-1,4-pregnadiene-3,20-dione) and 1.0 x 10(-4) M for epicortisol (11 alpha, 17,21-trihydroxy-4-pregnene-3,20-dione). The activity of purified bovine trypsin on its specific substrate, TAME (tosyl arginine methyl ester), also showed a similar pattern of inhibition by steroids. Both chymotrypsin and trypsin were found to bind 3H-labeled dexamethasone and cortisol. This binding was markedly inhibited by the general protease inhibitor, PMSF (phenylmethanesulfonyl fluoride), whereas the chymotrypsin-specific inhibitor, TPCK (L-[1-tosyl-amido-2-phenyl]ethylchloromethyl ketone), inhibited only the steroid binding to chymotrypsin but not to trypsin. These observations indicate that serine proteases recognize steroid hormones in a fashion similar to the recognition of their specific substrates and that the steroids inhibit activity of these enzymes at their binding sites.
已发现几种甾体激素可抑制纯化的牛胰凝乳蛋白酶对14C标记珠蛋白的蛋白水解作用以及对特定底物苯甲酰酪氨酸乙酯的水解作用。甾体激素对胰凝乳蛋白酶的抑制作用具有竞争性，曲安西龙（9-氟-11β，16α，17,21-四羟基-1,4-孕二烯-3,20-二酮）的Ki值为9.9×10^(-5) M，皮质醇（11β，17α，21-三羟基孕-4-烯-3,20-二酮）为1.6×10^(-4) M，睾酮（17β-羟基-4-雄烯-3-酮）为3.7×10^(-4) M，地塞米松（9-氟-11β，17,21-三羟基-16α-甲基-1,4-孕二烯-3,20-二酮）为5.0×10^(-4) M，表皮质醇（11α，17,21-三羟基-4-孕烯-3,20-二酮）为1.0×10^(-4) M。纯化的牛胰蛋白酶对其特定底物甲苯磺酰精氨酸甲酯（TAME）的活性也表现出类似的甾体激素抑制模式。已发现胰凝乳蛋白酶和胰蛋白酶均可结合3H标记的地塞米松和皮质醇。这种结合可被通用蛋白酶抑制剂苯甲基磺酰氟（PMSF）显著抑制，而胰凝乳蛋白酶特异性抑制剂L-[1-甲苯磺酰氨基-2-苯基]乙基氯甲基酮（TPCK）仅抑制甾体激素与胰凝乳蛋白酶的结合，而不抑制与胰蛋白酶的结合。这些观察结果表明，丝氨酸蛋白酶识别甾体激素的方式与其识别特定底物的方式相似，并且甾体激素在其结合位点抑制这些酶的活性。
