酶通过抑制它们的反应片段,实际上获得了多少?
1Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, USA.
Journal of the American Chemical Society
|April 11, 2002
概括
绝缘效应不是酶催化的主要驱动因素. 计算机模拟显示静电相互作用,而不是硬体力,是甲脱酶的关键.
科学领域:
- 生物化学 生物化学
- 计算化学的计算化学
- 酶催化酶的催化作用
背景情况:
- 酶催化通常归因于固态效应,将基质推入接近攻击配置 (NAC).
- 固体贡献与静电力在酶催化中的作用仍然是研究的主题.
- 甲脱酶作为研究催化机制的模型酶.
研究的目的:
- 用计算机模拟量化评估酶催化中的固体效应的相对重要性.
- 为了区分体和静电对醇脱酶的催化功率的贡献.
主要方法:
- 利用经验价值键 (EVB) 方法来建模反应电位表面.
- 采用热力学循环来比较酶反应与水中的反应.
- 开发了两个计算策略:在水中限制基板和消除静电相互作用.
主要成果:
- 发现非静电 (静态) 对催化物的贡献大约为-0.7 kcal/mol.
- 显而易见的硬化效应,包括静电贡献,为-2.2 kcal/mol.
- 静电相互作用占催化效应的大部分,约为-6.1 kcal/mol.
结论:
- 绝缘效应不是haloalkanedehalogenase中催化功能的主要来源.
- 静电相互作用在酶的催化效率中起着主导作用.
- 显而易见的硬化效应受到溶剂重组能量的显著影响,挑战了传统的观点.
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