...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochimica et Biophysica Acta. Protein Structure and Molecular Enzymology >Transition-state theoretical interpretation of the catalytic power of pyruvate decarboxylases: the roles of static and dynamical considerations
【24h】

Transition-state theoretical interpretation of the catalytic power of pyruvate decarboxylases: the roles of static and dynamical considerations

机译：丙酮酸脱羧酶催化能力的过渡态理论解释：静态和动态考虑的作用

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The catalytic power of two thiamin diphosphate (ThDP)-dependent enzymes, yeast pyruvate decarboxylase (the hysteretically regulated enzyme from Saccharomyces cerevisiae, SCPDC) and bacterial pyruvate decarboxylase (the unregulated enzyme from Zymomonas mobilis, ZMPDC), are analyzed by thorough-going application of transition-state theory, i.e. by a static approach that emphasizes the state-function character of the free energy of activation and takes no explicit account of dynamical considerations. The overall catalytic reaction is resolved into manifolds for addition (conversion of free enzyme and substrate to the complex of enzyme with the pyruvate : ThDP adduct), decarboxylation, and elimination (conversion of the complex of enzyme with the acetaldehyde : ThDP adduct formed by decarboxylation into the product and free enzyme). For SCPDC, the addition manifold is most strongly catalyzed (3 * 10~(12)-fold, corresponding to net transition-state stabilization of 72 kJ/mol, transition-state stabilization of 83 kJ/mol diminished by reactant-state stabilization of 11 kJ/mol), the decarboxylation manifold is least strongly catalyzed (5 * 10~7-fold, corresponding to net transition-state stabilization of 41 kJ/mol, transition-state stabilization of 68 kJ/mol diminished by reactant-state stabilization of 27 kJ/mol), and the elimination manifold is catalyzed to an intermediate degree (2 * 10~(10)-fold, corresponding to net transition-state stabilization of 59 kJ/mol, transition-state stabilization of 76 kJ/mol diminished by reactant-state stabilization of 17 kJ/mol). A similar situation holds of ZMPDC. There is no need to make an explicit analysis of dynamical factors in order to describe the catalytic mechanism and catalytic power of these complex enzymes.
机译：通过全面的应用分析了两种依赖于硫胺二磷酸（ThDP）的酶的催化能力，即酵母丙酮酸脱羧酶（来自酿酒酵母（Saccharomyces cerevisiae，SCPDC）的滞后调节酶）和细菌丙酮酸脱羧酶（来自运动发酵单胞菌（Zymomonas mobilis，ZMPDC）的不受调节酶）。过渡状态理论的理论基础，即通过强调活化自由能的状态函数特征的静态方法，而没有明确考虑动力学因素。整个催化反应分解为多种形式，用于添加（游离酶和底物转化为酶与丙酮酸的复合物：ThDP加合物），脱羧和消除（转化酶与乙醛的复合物：由脱羧形成的ThDP加合物）进入产品和游离酶）。对于SCPDC，加成歧管被最强地催化（3 * 10〜（12）倍，对应于72 kJ / mol的净过渡态稳定度，由于32kJ / mol的反应物态稳定度而降低的83 kJ / mol过渡态稳定度11 kJ / mol）时，脱羧歧管的催化作用最弱（5 * 10〜7倍，对应于41 kJ / mol的净过渡态稳定度，由于反应物状态的稳定化而降低的68 kJ / mol的过渡态稳定度）为27 kJ / mol），消除歧管被催化至中等程度（2 * 10〜（10）倍，对应于59 kJ / mol的净过渡态稳定度，76 kJ / mol的过渡态稳定度通过17 kJ / mol的反应物态稳定度降低）。 ZMPDC的情况与此类似。无需对动力学因素进行明确分析即可描述这些复杂酶的催化机理和催化能力。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号