Funaki T, Ichihara S, Fukazawa H, Kuruma I
Nippon Roche Research Center, Kanagawa, Japan.
Biochim Biophys Acta. 1991 Dec 11;1118(1):21-4. doi: 10.1016/0167-4838(91)90436-4.
We derived an equation which describes the plot of the remaining enzyme activity versus ratio of initial concentration of suicide substrate to that of enzyme to obtain a partition ratio from the time-course of remaining enzyme activity. The simulation data calculated from the representative kinetic model for a suicide substrate were used to verify this equation, which approximated steady state kinetics. Although the time-dependent loss of enzyme activity is usually characterized by pseudo-first-order kinetics, the present results show that pseudo-first-order kinetics are followed only when the ratio of initial concentration of suicide substrate to that of enzyme is greater than the partition ratio. Our results also show that the present method can be used to obtain the partition ratio of a suicide substrate from the time-course of the remaining enzyme activity when the suicide substrate is given an arbitrary concentration of one, where the ratio of initial concentration of suicide substrate to that of enzyme is less than the partition ratio. The theoretically verified equation was also checked against reported experimental data for a microsomal enzyme system.
我们推导了一个方程，该方程描述了剩余酶活性与自杀底物初始浓度与酶浓度之比的关系图，以便从剩余酶活性的时间进程中获得分配比。从自杀底物的代表性动力学模型计算得到的模拟数据用于验证该方程，该方程近似于稳态动力学。尽管酶活性随时间的损失通常以伪一级动力学为特征，但目前的结果表明，只有当自杀底物初始浓度与酶浓度之比大于分配比时，才遵循伪一级动力学。我们的结果还表明，当自杀底物的浓度被设定为任意一个值，且自杀底物初始浓度与酶浓度之比小于分配比时，本方法可用于从剩余酶活性的时间进程中获得自杀底物的分配比。还将理论验证的方程与微粒体酶系统的报道实验数据进行了对照。
