Srere P A
Department of Veterans Affairs, Medical Center, Dallas, TX 75216.
Biol Chem Hoppe Seyler. 1993 Sep;374(9):833-42.
Two of the most recent hypotheses concerning metabolism and its regulation are examined. First, the theory of distributive regulatory control of metabolic pathways is considered in light of experimental evidence concerning the lack of change in flux of a pathway when individual enzymes are either increased or decreased. In addition, it is known that when flux through pathways is either increased or decreased, one finds that the amount of all the enzymes of that path increase or decrease simultaneously. Second, the hypothesis of the existence of metabolons, complexes of sequential metabolic enzymes, is examined using the Krebs TCA cycle pathway as an example. The evidence from in vitro studies with pure enzymes to in vitro metabolic studies with yeast mutants is reviewed and evaluated. Unsolved problems concerning these hypotheses which still exist are considered.
本文考察了两个关于新陈代谢及其调控的最新假说。首先，鉴于有实验证据表明，当单个酶增加或减少时，代谢途径的通量并无变化，我们对代谢途径的分布式调控理论进行了探讨。此外，已知当通过途径的通量增加或减少时，人们会发现该途径中所有酶的量会同时增加或减少。其次，以克雷布斯三羧酸循环途径为例，对代谢体（即顺序代谢酶复合物）存在的假说进行了考察。我们回顾并评估了从使用纯酶的体外研究到使用酵母突变体的体外代谢研究的相关证据。文中还考虑了关于这些假说仍然存在的未解决问题。
