Pette D, Hofer H W
Ciba Found Symp. 1979(73):231-44. doi: 10.1002/9780470720561.ch13.
Comparative analyses of enzyme activity patterns reveal groups of enzymes with constant proportions and enzymes with variable proportions of their maximum activities. Constant proportion groups comprise enzymes of unbranched metabolic sequences or functionally related pathways. Ratios of constant proportion groups reflect metabolic correlations, which may be used as discriminative magnitudes of metabolic specialization. Comparison of closely related muscles reveals that differences in the absolute levels of the constant proportion group enzymes of glycolysis parallel differences in maximum glycolytic flux rates. This holds for near-equilibrium as well as for non-equilibrium enzymes. In any case, maximum enzyme activities are significantly higher than maximum metabolic flux rates. Maximum enzyme activities therefore do not permit conclusions on maximum metabolic capacities to be drawn. They may, however, be compared in closely related tissues or different metabolic conditions of a given tissue as relative magnitudes of maximum flux rates. Reference enzymes of constant proportion groups as well as of other enzymes which are representative of distinct metabolic pathways may be used in this sense for the evaluation of enzyme activity patterns. Selection of appropriate enzymes depends on the aim of the intended study, on a thorough knowledge of their individual properties, and on the possibility of measuring their maximum activity under reproducible conditions.
酶活性模式的比较分析揭示了具有恒定比例的酶组和最大活性比例可变的酶。恒定比例组包括无分支代谢序列或功能相关途径的酶。恒定比例组的比率反映了代谢相关性，可作为代谢特化的判别量度。对密切相关肌肉的比较表明，糖酵解恒定比例组酶的绝对水平差异与最大糖酵解通量率差异平行。这适用于近平衡酶和非平衡酶。在任何情况下，最大酶活性都显著高于最大代谢通量率。因此，不能根据最大酶活性得出最大代谢能力的结论。然而，在密切相关的组织或给定组织的不同代谢条件下，它们可以作为最大通量率的相对量度进行比较。从这个意义上说，恒定比例组的参考酶以及代表不同代谢途径的其他酶可用于评估酶活性模式。选择合适的酶取决于预期研究的目的、对其个体特性的透彻了解以及在可重复条件下测量其最大活性的可能性。
