mM, and k2 = 0.015 and 0.010 s-1, respectively). Inhibition of DPP-I by 3d provides only the second example of a cysteine protease which is strongly inhibited by a nitrile analogue of a specific substrate. Further studies are needed to determine the generality and potential utility of this finding. Compounds 3e, 3f, and 4e exemplify a new class of specific affinity labels for cysteine proteases whose
制备几种类型的羧基修饰的
氨基酸和肽,它们具有适合于几种代表性
蛋白酶之一的N末端修饰(载体片段),并评估了它们对这些酶的抑制作用。羧基修饰(抑制单元)包括(b)CONH 2,(c)CSNH 2,(d)CN,(e)反式-CH = CHCO 2 Me和(f)反式-CH = CHSO 2 Me。载体片段包括NH2(PhCH2)CHX(1),AcNH(PhCH2)CHX(2),H2NCH2CONH(PhCH2)CHX(3)和AcNH(PhCH2)CHCONHCH2X(4)。化合物1b,1d,1e和1f是微粒体和胞质亮
氨酸
氨基肽酶的竞争性
抑制剂(前者的Ki分别为14.8、67、61和3.7 mM,后者分别为14.1、26.4、27.3和8.8 mM) 。化合物1c和亮
氨酸
硫代酰胺均对这两种酶均无任何可检测的作用。化合物2b-f还是胰凝乳
蛋白酶的竞争性
抑制剂(Ki分别为13.9、23.0、5.3、30.8和29