Klinov S V, Sugrobova N P, Kurganov B I
Mol Biol (Mosk). 1979 May-Jun;13(3):559-66.
It has been shown that the binding of pig skeletal muscle lactate dehydrogenase (isozyme M4) by dextran sulfate with weight-average molecular weight 500 000 is accompanied by a decrease of the rate of enzymatic reduction of pyruvate. The hyperbolic dependence of the enzymic reaction rate on NADH concentration observed for free lactate dehydrogenase is transformed in a sigmoidal curve in the case of adsorbed enzyme form (Hill's coefficient is equal to 2.1). The experimental data have been described quantitatively using the model of adsorptive enzyme system where the enzyme interacts reversibly with the support and co-operative interaction of substrate binding sites in the adsorbed enzyme molecule are realized. It is assumed that the value of microscopic dissociation constant for the complex of the substrate with adsorbed enzyme is being changed by a constant factor during saturation of the binding sites by the substrate in the enzyme molecule. The value of parameters of the model for the adsorptive enzyme system under study are determined.
已表明，重均分子量为500000的硫酸葡聚糖与猪骨骼肌乳酸脱氢酶（同工酶M4）的结合伴随着丙酮酸酶促还原速率的降低。对于游离乳酸脱氢酶观察到的酶促反应速率对NADH浓度的双曲线依赖性，在吸附酶形式的情况下转变为S形曲线（希尔系数等于2.1）。使用吸附酶系统模型对实验数据进行了定量描述，其中酶与载体可逆相互作用，并且在吸附的酶分子中实现了底物结合位点的协同相互作用。假定在酶分子中底物使结合位点饱和的过程中，底物与吸附酶复合物的微观解离常数的值以恒定因子变化。确定了所研究的吸附酶系统模型的参数值。
