Ermakov G L, Goldstein B N
Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
Biochemistry (Mosc). 1997 Jun;62(6):583-95.
The structure-function organization of mammalian pyruvate dehydrogenase complex (PDC) is considered. The linear size of the complex components in relation to the size of their fragments and mean distances between potentially active sites are estimated. A kinetic model for the complex with core subunits divided into conformational classes characterized by their different activities is discussed. The kinetic features of this model are compared with the features of the model for the core subunits not divided into classes. Curves are described for the activity of PDC versus time for various activities of the kinase and the phosphatase as dependent on their binding to more or less active core subunits. The results show that spatially distributed multiple active sites in the multi-enzyme complex can drastically change their full activity in time without any marked changes in the rate constants of the elementary reaction steps due only to spatially changed reaction pathways. A new type of regulation discussed for PDC reveals unusual regulatory abilities for complexes of this family.
本文探讨了哺乳动物丙酮酸脱氢酶复合体（PDC）的结构-功能组织。估算了复合体各组分的线性尺寸与其片段大小以及潜在活性位点之间的平均距离。讨论了一个动力学模型，该模型将核心亚基分为具有不同活性的构象类别。将该模型的动力学特征与未分类的核心亚基模型的特征进行了比较。描述了在激酶和磷酸酶的各种活性下，PDC活性随时间变化的曲线，这些活性取决于它们与活性或多或少的核心亚基的结合情况。结果表明，多酶复合体中空间分布的多个活性位点可随时间急剧改变其总活性，而基本反应步骤的速率常数不会因空间反应途径的改变而发生任何显著变化。为PDC讨论的一种新型调节方式揭示了该家族复合体不同寻常的调节能力。
