Alberty Robert A
Department of Chemistry, Massachusetts Instiute of Technology, Cambridge, Massachusetts 02139, USA.
J Phys Chem B. 2009 Jan 29;113(4):1225-31. doi: 10.1021/jp8080436.
Rapid-equilibrium rate equations are derived for the five different mechanisms for the enzymatic catalysis of A + B + C --> products using a computer. These rate equations are used to determine the minimum number of velocities required to estimate the values of the kinetic parameters. The rate equation for the completely ordered mechanism involves four kinetic parameters, and the rate equation for the completely random mechanism involves eight kinetic parameters. Therefore, the four to eight kinetic parameters can be estimated by determining four to eight velocities and solving four to eight simultaneous equations. General recommendations are made as to the choices of triplets of substrate concentrations {[A], [B], [C]} to be used to determine the velocities. The effects of 5% errors in the measured velocities, one at a time, are calculated and are summarized in tables. Calculations of effects of experimental errors are useful in choosing the triplets of substrate concentrations to be used to obtain the most accurate values of the kinetic parameters. When the kinetic parameters for A + B + C --> products are to be determined for the first time, it is recommended that the program for the completely random mechanism be used because it can identify the mechanism and determine the kinetic parameters in one operation.
使用计算机推导出了A + B + C→产物酶催化的五种不同机制的快速平衡速率方程。这些速率方程用于确定估计动力学参数值所需的最小速度数量。完全有序机制的速率方程涉及四个动力学参数，完全随机机制的速率方程涉及八个动力学参数。因此，可以通过确定四到八个速度并求解四到八个联立方程来估计四到八个动力学参数。针对用于确定速度的底物浓度三元组{[A]、[B]、[C]}的选择给出了一般建议。一次计算测量速度中5%误差的影响，并汇总在表格中。实验误差影响的计算有助于选择用于获得最准确动力学参数值的底物浓度三元组。当首次确定A + B + C→产物的动力学参数时，建议使用完全随机机制的程序，因为它可以在一次操作中识别机制并确定动力学参数。
