[晶状体醛糖还原酶活性的调节。葡萄糖对NADPH的非双曲线氧化动力学]

[Regulation of crystalline lens aldose reductase activity. Nonhyperbolic oxidation kinetics of NADPH by glucose].

作者信息

Vartanov S S, Pavlov A R, Iaropolov A I

出版信息

Biokhimiia. 1990 Nov;55(11):2046-57.

Abstract

A homogeneous aldose reductase was isolated from bovine eye lens tissue by using affinity chromatography on blue agarose. A kinetic analysis of the initial rates of NADPH oxidation at 0.5-100 mM glucose and at 1.2-10 microM NADPH was carried out. The Line-weaver-Burk plots for glucose concentration were nonlinear at fixed concentrations of NADPH and linear at fixed concentrations of glucose. It was shown that the experimental plots reflect the mechanisms, in which substrate regulation of enzyme activity is effectuated by glucose binding to the regulatory site or is due to the shift of the equilibrium between the isomeric forms of aldose reductase.

摘要

通过在蓝色琼脂糖上进行亲和层析，从牛眼晶状体组织中分离出一种均一的醛糖还原酶。对在0.5 - 100 mM葡萄糖和1.2 - 10 μM NADPH条件下NADPH氧化的初始速率进行了动力学分析。在固定NADPH浓度下，葡萄糖浓度的Line - weaver - Burk图呈非线性，而在固定葡萄糖浓度下呈线性。结果表明，实验图反映了这样的机制，即酶活性的底物调节是通过葡萄糖与调节位点结合实现的，或者是由于醛糖还原酶异构体形式之间平衡的移动所致。