MacGibbon A K, Haylock S J, Buckley P D, Blackwell L F
Biochem J. 1978 Jun 1;171(3):533-8. doi: 10.1042/bj1710533.
The hydrolysis of 4-nitrophenyl acetate catalysed by cytoplasmic aldehyde dehydrogenase (EC 1.2.1.3) from sheep liver was studied by steady-state and transient kinetic techniques. NAD+ and NADH stimulated the steady-state rate of ester hydrolysis at concentrations expected on the basis of their Michaelis constants from the dehydrogenase reaction. At higher concentrations of the coenzymes, both NAD+ and NADH inhibited the reaction competitively with respect to 4-nitrophenyl acetate, with inhibition constants of 104 and 197 micron respectively. Propionaldehyde and chloral hydrate are competitive inhibitors of the esterase reaction. A burst in the production of 4-nitrophenoxide ion was observed, with a rate constant of 12 +/- 2s-1 and a burst amplitude that was 30% of that expected on the basis of the known NADH-binding site concentration. The rate-limiting step for the esterase reaction occurs after the formation of 4-nitrophenoxide ion. Arguments are presented for the existence of distinct ester- and aldehyde-binding sites.
采用稳态和瞬态动力学技术研究了绵羊肝脏细胞质醛脱氢酶（EC 1.2.1.3）催化乙酸对硝基苯酯的水解反应。NAD⁺和NADH按照脱氢酶反应中基于其米氏常数所预期的浓度刺激酯水解的稳态速率。在辅酶浓度较高时，NAD⁺和NADH均相对于乙酸对硝基苯酯竞争性抑制该反应，抑制常数分别为104和197微摩尔。丙醛和水合氯醛是酯酶反应的竞争性抑制剂。观察到对硝基苯氧离子的生成出现一个突发过程，速率常数为12±2 s⁻¹，突发幅度是基于已知NADH结合位点浓度预期值的30%。酯酶反应的限速步骤发生在对硝基苯氧离子形成之后。文中提出了存在不同酯结合位点和醛结合位点的论据。
