Srivastava S K, Ansari N H, Hair G A, Jaspan J, Rao M B, Das B
Biochim Biophys Acta. 1986 Mar 28;870(2):302-11. doi: 10.1016/0167-4838(86)90234-7.
Incubation of human erythrocytes with varying concentrations of glucose resulted in a several-fold increase in aldose reductase (alditol:NADP+ 1-oxidoreductase, EC 1.1.1.21) activity as determined by the rate of NADPH oxidation and the rate of sorbitol formation. As compared to aldose reductase from human erythrocytes not incubated with glucose (native enzyme), aldose reductase from 30 mM glucose-incubated erythrocytes (activated enzyme) exhibited altered kinetic and inhibition properties. Native enzyme showed biphasic kinetics with substrates (glucose and glyceraldehyde), was strongly inhibited by 15 microM ADP, 1,3-diphosphoglycerate, 2,3-diphosphoglycerate and 3-phosphoglycerate, and aldose reductase inhibitors such as sorbinil and alrestatin. The activated enzyme, on the other hand, exhibited monophasic kinetics, low Km for substrates, was not inhibited by the phosphorylated intermediates, and was less susceptible to inhibition by aldose reductase inhibitors. In erythrocytes of the diabetic subjects, we have found an excellent correlation between aldose reductase activity and plasma glucose levels and have observed that whenever the blood glucose level was higher than 15 mM, all of the erythrocyte aldose reductase was present in the activated form and exhibited properties similar to those observed with aldose reductase obtained from 30 mM glucose-incubated erythrocytes.
用不同浓度的葡萄糖孵育人红细胞，通过NADPH氧化速率和山梨醇生成速率测定发现，醛糖还原酶（醛糖醇：NADP⁺ 1-氧化还原酶，EC 1.1.1.21）活性增加了几倍。与未用葡萄糖孵育的人红细胞中的醛糖还原酶（天然酶）相比，用30 mM葡萄糖孵育的红细胞中的醛糖还原酶（活化酶）表现出改变的动力学和抑制特性。天然酶对底物（葡萄糖和甘油醛）表现出双相动力学，受到15 μM ADP、1,3-二磷酸甘油酸、2,3-二磷酸甘油酸和3-磷酸甘油酸以及醛糖还原酶抑制剂如索比尼尔和阿雷司他汀的强烈抑制。另一方面，活化酶表现出单相动力学，对底物的Km值较低，不受磷酸化中间体的抑制，并且对醛糖还原酶抑制剂的抑制作用较不敏感。在糖尿病患者的红细胞中，我们发现醛糖还原酶活性与血浆葡萄糖水平之间存在极好的相关性，并且观察到每当血糖水平高于15 mM时，所有红细胞醛糖还原酶都以活化形式存在，并且表现出与从用30 mM葡萄糖孵育的红细胞中获得的醛糖还原酶相似的特性。
