CARBOXYPEPTIDASE-A MECHANISMS
CARBOXYPEPTIDASE-A MECHANISMS
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DOI：
10.1073/pnas.77.7.3875
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
LIPSCOMB, WN
中科院分区：
文献类型：
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作者：
LIPSCOMB, WN
酮底物是酯的类似物，其中易裂键的O被CH 2取代，酮底物与羧肽酶A的结合模式与Gly-Tyr的结合模式相似。位点是S1，侧链在酶的口袋中，羧酸盐连接到Arg-145，羰基结合到Zn。酯可能在肽裂解位点裂解，尽管不一定具有相同的速率控制步骤或通过相同的详细机制。在溶液中和在一个结晶相中发现的酶行为之间的巨大差异不适用于不同的结晶相。
The mode of binding of a ketonic substrate, which is an analog of esters in which the O of the scissile bond is replaced by CH2, to carboxypeptidase A is similar to that of Gly-Tyr. The site is S1, with the side chain in the pocket of the enzyme, the carboxylate salt-linked to Arg-145, and the carbonyl group bound to Zn. Esters are probably cleaved at the peptide cleavage site, although not necessarily with the same rate-controlling step or by the same detailed mechanism. The large differences found between the behavior of the enzyme in solution and in one crystalline phase do not apply to a different crystalline phase.