Letter: Micelle catalyzed reactions are models of enzyme catalyzed reactions which show positive homotropic interactions.
Letter: Micelle catalyzed reactions are models of enzyme catalyzed reactions which show positive homotropic interactions.
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DOI：
10.1021/ja00426a083
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发表时间：
1976-05
影响因子：
15
通讯作者：
D. Piszkiewicz
中科院分区：
文献类型：
--
作者：
D. Piszkiewicz
为了了解酶催化反应的机制，化学家花费了大量精力来研究更简单的化学系统中的催化作用。 1 从这个角度出发，对胶束内反应的催化进行了广泛的研究2· 3，因为胶束和酶都以非共价方式结合底物。本报告的目的是证明胶束催化和酶催化的额外相似性：胶束催化反应的动力学与许多调节酶的动力学相似，因为它们表现出正向同向相互作用。 4 酶促同向相互作用的简单动力学描述可应用于大量胶束催化反应的动力学分析。当绘制胶束催化反应的速率常数与洗涤剂浓度时，产生近似 S 形曲线；对于胶束抑制反应的情况，也观察到向下倾斜的 S 形曲线。这些曲线的形状与许多调节酶产生的速度对底物浓度的 S 形依赖性非常相似。通常用于定量描述速率常数与洗涤剂浓度关系的动力学模型假设胶束 D „ 在催化发生之前与底物 S 形成非共价复合物。3
In attempting to understand the mechanisms by which en-zymes catalyze reactions, chemists have expended much effort in the study of catalysis in simpler, chemical systems. 1 Catal-ysis of reactions within micelles has been studied extensively from this point of view2· 3 since both micelles and enzymes bind substrates in a noncovalent manner. The purpose of this report is to demonstrate an additional similarity of micelle catalysis and enzymatic catalysis: the kinetics of micelle catalyzed re-actions are similar to those of many regulatory enzymes in that they show positive homotropic interactions. 4 A simple kinetic description of enzymatic homotropic interactions may be ap-plied to analysis of the kinetics of a vast number of micelle catalyzed reactions.The rate constants for micelle catalyzed reactions when plotted vs. detergent concentration yield approximately sigmoid-shaped curves; downward sloping sigmoid curves have also been observed for cases in which micelles inhibit reaction. The similarities in shape of these curves to thesigmoid-shaped dependencies of velocity on substrate concentration produced by many regulatory enzymes are striking. The kinetic model commonly used to quantitatively describe the relationship of rate constant to detergent concentration assumes that micelle, D „, forms a noncovalent complex with substrate, S, before catalysis may take place. 3