Department of Chemistry, Massachusetts Institute of Technology, Room 6-215, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
J Phys Chem B. 2010 Feb 4;114(4):1684-9. doi: 10.1021/jp908023u.
Modifiers of enzyme-catalyzed reactions can have various types of effects on the velocity, but the most important effect is that they provide multiple pathways to products. The rapid-equilibrium kinetic effects of modifiers are explored for the enzyme-catalyzed reaction A --> products. When a single molecule of modifier X is bound, the mechanism involves three independent equilibrium expressions and two rate constants. But when two molecules of X are bound are bound in two reactions, there are five independent equilibria and three paths to products. The advantages of using a computer to derive rapid-equilibrium rate equations are that more complicated rate equations can be derived and the kinetic parameters can be estimated using the minimum number of velocity measurements. The mechanism with three paths to products is of special interest because the effects of cooperativity can be studied. Thermodynamic cycles can be used to estimate additional kinetic parameters.
酶促反应的调节剂可以对速度产生各种类型的影响，但最重要的影响是它们为产物提供了多种途径。本文探讨了酶促反应 A → 产物中调节剂的快速平衡动力学效应。当单个 X 调节剂分子结合时，该机制涉及三个独立的平衡表达式和两个速率常数。但是，当两个 X 分子结合时，有五个独立的平衡和三条产物途径。使用计算机推导快速平衡速率方程的优点是可以推导更复杂的速率方程，并使用最少数量的速度测量值来估计动力学参数。具有三条产物途径的机制特别有趣，因为可以研究协同作用的影响。热力学循环可用于估计其他动力学参数。
