Aragón J J, Sols A
Departamento de Bioquímica de la UAM, Facultad de Medicina de la Universidad Autónoma, Madrid, Spain.
FASEB J. 1991 Nov;5(14):2945-50. doi: 10.1096/fasebj.5.14.1752361.
The rapid development in our understanding of the regulation of enzyme activity makes it a high priority to ascertain whether the behavior of purified enzymes reflects their functional characteristics in vivo. Enzyme concentration is usually the most significant difference between routine in vitro assays and in vivo conditions, as it is well known that many intracellular enzymes are present in vivo at much higher concentrations than used in vitro. Various procedures are suitable for kinetic analysis at physiological concentrations of enzyme. Those more frequently used have been cell permeabilization, the utilization of purified enzymes at concentrations close to the in vivo range, and the addition of polyethylene glycol to increase the local protein concentration. In this review we briefly summarize observations on enzymes reported to exhibit concentration-dependent activity. The effect of enzyme concentration has been most thoroughly investigated in the case of phosphofructokinase. These studies may provide insight into the regulation of this important enzyme in the cell. The implications of both homologous and heterologous protein-protein interactions for the effect of enzyme concentration and their roles in the control of enzyme activity in vivo are also discussed.
随着我们对酶活性调节的理解迅速发展，确定纯化酶的行为是否反映其在体内的功能特性成为当务之急。酶浓度通常是常规体外测定与体内条件之间最显著的差异，因为众所周知，许多细胞内酶在体内的浓度比体外使用的浓度高得多。各种方法适用于在酶的生理浓度下进行动力学分析。那些更常用的方法包括细胞透化、在接近体内范围的浓度下使用纯化酶以及添加聚乙二醇以增加局部蛋白质浓度。在这篇综述中，我们简要总结了关于据报道表现出浓度依赖性活性的酶的观察结果。在磷酸果糖激酶的情况下，对酶浓度的影响进行了最深入的研究。这些研究可能为深入了解细胞中这种重要酶的调节提供线索。还讨论了同源和异源蛋白质 - 蛋白质相互作用对酶浓度效应的影响及其在体内酶活性控制中的作用。
