Extreme state of ionization of benzylsuccinate bound by carboxypeptidase A.
Extreme state of ionization of benzylsuccinate bound by carboxypeptidase A.
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羧肽酶 A 结合的琥珀酸苄酯的极端电离状态。
DOI：
10.1021/bi00263a032
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发表时间：
1982
期刊：
影响因子：
2.9
通讯作者：
Wolfenden,R
中科院分区：
文献类型：
--
作者：
Palmer,AR;Ellis,PD;Wolfenden,R
艾伦河Palmer，Paul D. Ellis和Richard Wolfenden* 摘要：苄基琥珀酸是一种强效的羧肽酶A抑制剂，在溶液中带有单个负电荷的pH值下表现出最大抑制作用。为了确定酶-抑制剂复合物中的电荷分布，在每个酶-抑制剂复合物中富集13 C，2-苄基琥珀酸是羧肽酶A的非常强大的可逆抑制剂，与肽和酯底物的水解竞争（Byers & Wolfenden，1972，1973）。这种抑制剂（图1A）已经用作设计拮抗血管紧张素转化酶的药物的出发点（Cushman等人，1977; Patchett等人，1980）和作为用于分离羧基肽酶的亲和配体（Peterson等人，1976年）。琥珀酸苄酯与底物水解的化学中间体没有明显的结构相似性，其对羧肽酶A的亲和力也不随pH的变化而变化，这种变化类似于pH对Fm的影响，对于正常底物，这可能是理想的过渡态类似物。从稀溶液中收集几种底物分子的能量负担减轻后，通常预期酶显示出与“多底物类似物”的亲和力，其匹配或超过它们对单个底物的组合亲和力（Wolfenden，1972）。琥珀酸苄酯对羧肽酶的不寻常的亲和力似乎可以理解，因为它与肽的收集产物相似。
Allen R. Palmer, Paul D. Ellis, and Richard Wolfenden* abstract: Benzylsuccinic acid, a powerful inhibitorof car-boxypeptidase A, exhibits maximum inhibition at pH values where the inhibitor bears a single negative charge in solution. To establish the distribution of charges in the enzyme-inhibitor complex, this inhibitor was enriched with 13C at each of the2-Benzylsuccinate is an exceptionally powerful reversible inhibitor of carboxypeptidase A, competitive against hydrolysis of peptide and ester substrates (Byers & Wolfenden, 1972, 1973). This inhibitor (Figure 1A) has served as a point of departure for the design of drugs antagonistic to angiotensin-converting enzyme (Cushman et al., 1977; Patchett et al., 1980) and as an affinity ligand for the isolation of carboxy-peptidases (Peterson et al., 1976). Benzylsuccinate bears no obvious structural resemblance to chemical intermediates in substrate hydrolysis, nor does its affinity forcarboxypeptidase A change with changing pH in a way that resembles the influence of pH on Fm, for normal substrates, as might be expected for an ideal transition-state analogue. Relieved of the energetic burden of gathering several substrate molecules from dilute solution, enzymes are generally expected to show affinities for “multisubstrate analogues” that match or surpass their combined affinities for the individual substrates (Wolfenden, 1972). The unusual affinity of ben-zylsuccinate for carboxypeptidase seemed understandable in terms of its resemblance to the collected product of peptide