Aflalo C, Azoulay H
Department of Life Sciences, The Ben Gurion University of the Negev, Beer Sheva, Israel.
J Bioenerg Biomembr. 1998 Jun;30(3):245-55. doi: 10.1023/a:1020544803475.
Heterologous binding of rat brain hexokinase to wild type, porinless, and recombinant yeast mitochondria expressing human porin was assessed, partially characterized, and compared to that in the homologous system (rat liver mitochondria). With porin-containing yeast mitochondria it is shown that (i) a significant, saturable association occurs; (ii) its extent and apparent affinity, correlated with the origin of porin, are enhanced in the presence of dextran; (iii) the binding requires Mg ions and apparently follows a complex cooperative mechanism. This heterologous association does not seem to differ fundamentally from that in the homologous system and represents a good basis for molecular studies in yeast. With porinless yeast mitochondria, binding occurs at much lower affinity, but to many more sites per mitochondrion. The results indicating a major but not exclusive role for porin in the binding are discussed in terms of (i) the mode and mechanism of binding, and (ii) the suitability of the rat hexokinase-yeast mitochondria couple for the study of heterogeneous catalysis in reconstituted cellular model systems.
评估了大鼠脑己糖激酶与表达人孔蛋白的野生型、无孔蛋白和重组酵母线粒体的异源结合，对其进行了部分表征，并与同源系统（大鼠肝线粒体）中的结合进行了比较。对于含孔蛋白的酵母线粒体，研究表明：（i）发生了显著的、可饱和的结合；（ii）其程度和表观亲和力与孔蛋白的来源相关，在葡聚糖存在下增强；（iii）结合需要镁离子，且显然遵循复杂的协同机制。这种异源结合似乎与同源系统中的结合没有根本差异，是酵母分子研究的良好基础。对于无孔蛋白的酵母线粒体，结合以低得多的亲和力发生，但每个线粒体的结合位点更多。从（i）结合模式和机制，以及（ii）大鼠己糖激酶 - 酵母线粒体对在重组细胞模型系统中研究异质催化的适用性方面，讨论了表明孔蛋白在结合中起主要但非排他性作用的结果。
