鸡肝线粒体苹果酸脱氢酶的动力学机制（作者译）

[Kinetic mechanism of chicken liver mitochondrial malatedehydrogenase (author's transl)].

作者信息

Casadó F, Cortés A, Bozal J

出版信息

Rev Esp Fisiol. 1979 Jun;35(2):229-38.

Abstract

Kinetic mechanism of chicken liver mitochondrial malatedehydrogenase is established from the initial reaction rates and reaction product inhibition. The results obtained in the reduction of NAD+ (pH 10) allow the formulation of an ordered bi-bi mechanism in which the coenzyme is the first substrate added to the enzyme. Inhibition by the reaction products and by the excess of the very substrates, reveals the formation of the E-oxaloacetate; E-L-malate; E-NAD+-oxaloacetate; E.NAD+-NADH; E-NADH-NADH and E-NAD-NAD+ abortive complexes, the significance of which may be checked under defined experimental conditions. Enzyme inhibition by ATP, ADP and AMP in the reduction of NAD+ (pH10), accords with the proposed mechanism and proceeds via formation of the E-nucleotide and E-NAD+-nucleotide inactive complexes.

摘要

通过初始反应速率和反应产物抑制作用建立了鸡肝线粒体苹果酸脱氢酶的动力学机制。在NAD⁺还原反应（pH 10）中获得的结果支持有序双底物双产物机制，其中辅酶是添加到酶上的第一个底物。反应产物和过量底物的抑制作用揭示了E-草酰乙酸、E-L-苹果酸、E-NAD⁺-草酰乙酸、E·NAD⁺-NADH、E-NADH-NADH和E-NAD-NAD⁺无效复合物的形成，其重要性可在特定实验条件下进行检验。在NAD⁺还原反应（pH10）中，ATP、ADP和AMP对酶的抑制作用符合所提出的机制，并通过形成E-核苷酸和E-NAD⁺-核苷酸无活性复合物进行。