Chou K C, Forsén S
Biophys Chem. 1980 Dec;12(3-4):255-63. doi: 10.1016/0301-4622(80)80002-0.
In this paper the diffusion-controlled effects in reversible enzyme fast reaction systems have been discussed. The main results are as follows: 1) An expression for the relation between the proximity second-order rate constant and the usual experimental second-order rate constant has been presented. From this expression we can see that the two kinds of rate constants are generally not equal unless the reaction proceeds very slowly (in comparison with the corresponding diffusion limit). 2) A new joint relation has been given between the theoretical calculated results and the experimentally measured ones for the activation energy. It has been pointed out that, for the reaction systems discussed here, it would no longer be valid to adopt the absolute reaction rate theory to calculate the activation energy as done commonly. 3) A formula has been given to calculate the upper limit obtainable possibly by experiments for the second-order rate constants in the reversible enzymatic fast reaction system. According to this formula, the value of such an upper limit is related not only to the diffusion coefficients of reacting molecules, the size of active surface, and the like, but also to the ratio of the concentration of product molecules to that of the substrate molecules at the equilibrium of the reaction system. Furthermore, the reversible enzymatic fast reaction system with multi-substrate and multi-product has been discussed, and a general equation for calculating the degree of reaction flow derived as well.
本文讨论了可逆酶促快速反应体系中的扩散控制效应。主要结果如下：1）给出了邻近二级速率常数与通常实验二级速率常数之间关系的表达式。从该表达式可以看出，除非反应进行得非常缓慢（与相应的扩散极限相比），否则这两种速率常数通常不相等。2）给出了理论计算结果与实验测量的活化能之间的新的联合关系。已经指出，对于这里讨论的反应体系，像通常那样采用绝对反应速率理论来计算活化能将不再有效。3）给出了一个公式，用于计算可逆酶促快速反应体系中二级速率常数可能通过实验获得的上限。根据这个公式，这样一个上限的值不仅与反应分子的扩散系数、活性表面的大小等有关，而且还与反应体系平衡时产物分子浓度与底物分子浓度的比值有关。此外，还讨论了具有多底物和多产物的可逆酶促快速反应体系，并推导了计算反应流程度的通用方程。
