Kuhn R W, Walsh K A, Neurath H
Biochemistry. 1976 Nov 2;15(22):4881-5. doi: 10.1021/bi00667a020.
The reactions between yeast carboxypeptidase C and the group-specific reagents, phenylglyoxal and iodoacetamide, have been studied in detail and the reactions of residue at the active site with N-tosyl-L-phenylalanine chloromethyl ketone and diisopropyl phosphorofluoridate have been confirmed. Modification of the enzyme by either phenylglyoxal or iodoacetamide results in the loss of peptidase activity, while esterase activity remains unchanged. Inactivation by phenylglyoxal appears to be the result of the modification of a single arginine residue, whereas inhibition by iodoacetamide can be correlated with the modification of a single methionine residue. Inactivation of the enzyme by either N-tosyl-L-phenylalanine chloromethyl ketone or diisopropyl phosphorofluoridate is the result of the modification of a single histidine and a single serine residue, respectively. The pattern of inhibition indicates certain analogies in the mechanism of yeast carboxypeptidase C to pancreatic chymotrypsin, on the one hand, and to carboxypeptidase A, on the other.
已详细研究了酵母羧肽酶C与基团特异性试剂苯乙二醛和碘乙酰胺之间的反应，并证实了活性位点残基与N-对甲苯磺酰-L-苯丙氨酸氯甲基酮和二异丙基氟磷酸酯的反应。用苯乙二醛或碘乙酰胺对该酶进行修饰会导致肽酶活性丧失，而酯酶活性保持不变。苯乙二醛导致的失活似乎是单个精氨酸残基修饰的结果，而碘乙酰胺的抑制作用则与单个甲硫氨酸残基的修饰有关。N-对甲苯磺酰-L-苯丙氨酸氯甲基酮或二异丙基氟磷酸酯导致的酶失活分别是单个组氨酸和单个丝氨酸残基修饰的结果。抑制模式表明，酵母羧肽酶C的作用机制一方面与胰凝乳蛋白酶有某些相似之处，另一方面与羧肽酶A有某些相似之处。
