Doughty C C, Conrad S M
Biochim Biophys Acta. 1982 Nov 19;708(3):358-64. doi: 10.1016/0167-4838(82)90449-6.
Sheys and Doughty, (Sheys, G.H. and Doughty, C.C. (1979) Biochim. Biophys. Acta 242, 523-531) suggested a model for Rhodotorula (yeast) aldose reductase (alditol:NADP+ 1-oxidoreductase, EC 1.1.1.21) which offered a unified explanation for changes in reversibility, reaction mechanism, and effects of multivalent anions as well as substrate activation. The present paper extends this model to lens aldose reductase, explaining its similarities to the reverse reaction in Rhodotorula in regard to its reaction mechanism, as well as multivalent anion effects of sulfate, pyrophosphate and NADPH (above 20 micro M) and also substrate activation with glyceraldehyde involving formation of an abortive complex (above 50 micro M). Activation of lens aldose reductase resulted with multivalent anions, due to increased V max and apparent Km values with increasing concentration of multivalent anions. The lens enzyme mechanism is similar to the reverse reaction mechanism for the Rhodotorula enzyme, being partially random in character, based on NADP+ inhibitor studies presented here. The binding of NADPH appears to occur at a basic center containing arginine and possibly histidine. Evidence of the participation of these residues at the active center is based on time-course inactivation protection studies using reagents specific for these residues.
谢伊斯和道蒂（谢伊斯，G.H. 和道蒂，C.C.（1979 年）《生物化学与生物物理学报》242 卷，523 - 531 页）提出了一种红酵母（酵母）醛糖还原酶（醛糖醇：NADP⁺ 1 - 氧化还原酶，EC 1.1.1.21）的模型，该模型对可逆性变化、反应机制、多价阴离子的影响以及底物激活提供了统一的解释。本文将该模型扩展至晶状体醛糖还原酶，解释了其在反应机制方面与红酵母中逆向反应的相似性，以及硫酸盐、焦磷酸盐和 NADPH（浓度高于 20 μM）的多价阴离子效应，还有甘油醛（浓度高于 50 μM）的底物激活涉及形成无效复合物。随着多价阴离子浓度增加，Vmax 和表观 Km 值升高，多价阴离子导致晶状体醛糖还原酶被激活。基于此处呈现的 NADP⁺抑制剂研究，晶状体酶机制与红酵母酶的逆向反应机制相似，具有部分随机的特征。NADPH 的结合似乎发生在一个含有精氨酸且可能还有组氨酸的碱性中心。这些残基在活性中心参与作用的证据基于使用针对这些残基的特异性试剂进行的时间进程失活保护研究。
