HOW DO SERINE PROTEASES REALLY WORK
HOW DO SERINE PROTEASES REALLY WORK
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DOI：
10.1021/bi00435a001
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发表时间：
1989-05-02
期刊：
影响因子：
2.9
通讯作者：
HWANG, JK
中科院分区：
文献类型：
--
作者：
WARSHEL, A;NARAYSZABO, G;HWANG, JK
南加州大学化学系，洛杉矶，加利福尼亚州，90089-0482收到1988年12月27日；修订稿收到1989年2月16日摘要：基因工程的最新进展使人们越来越多地接受这样一个事实，即酶通过减少相应反应的激活障碍而像其他催化剂一样起作用。然而，关于酶的作用的关键问题与它们稳定过渡态的事实无关，而是与它们如何完成这一任务的问题有关。这项工作考虑了丝氨酸蛋白酶的催化反应，并演示了如何结合计算和实验信息来阐明对催化自由能的关键贡献。分析了最近关于丝氨酸蛋白酶中埋藏的天冬氨酸基团的遗传修饰的报道，这建立了这一基团的巨大作用(但无法确定其来源)。两种独立的方法表明，丝氨酸蛋白酶中埋藏的天冬氨酸基团通过静电相互作用而不是通过替代机制来稳定过渡态。简单的自由能考虑被用来消除双质子转移机制(在许多教科书中被描述为关键的催化因素插入蛋白水解酶)。还考虑了过渡态中含氧阴离子一侧的静电稳定作用。有人认为，丝氨酸蛋白酶和其他酶的工作原理是为它们催化的反应过程中发生的电荷分布变化提供静电互补。
Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482 Received December 27, 1988; Revised Manuscript Received February 16, 1989 abstract: Recent advances in genetic engineering have led to a growing acceptance of the fact that enzymes work like other catalysts by reducing the activation barriers of the corresponding reactions. However, the key question about the action of enzymes is not related to the factthat they stabilize transition states but to the question to how they accomplish this task. This work considers the catalytic reaction of serine proteases and demonstrates how one can use a combination of calculations and experimental information to elucidate the key contributions to the catalytic free energy. Recent reports about genetic modifications of the buried aspartic group in serineproteases, which established the large effect of this group (but could not determine its origin), are analyzed. Two independent methods indicate that the buried aspartic group in serine proteases stabilizes the transition state by electrostatic interactions rather than by alternative mechanisms. Simple free energy considerations are used to eliminate the double proton-transfer mechanism (which is depicted in many textbooks as the key catalytic factor inserine proteases). The electrostaticstabilization of the oxyanion side of the transition state is also considered. It is argued that serine proteases and other enzymes work by providing electrostatic complementarity to the changes in charge distribution occurring during the reactions they catalyze.