ALDOSE REDUCTASE AND DIABETIC COMPLICATIONS

糖尿病的一些并发症，如白内障，视网膜病变， 神经病和肾病在患有 糖尿病会持续一段时间。山梨醇的积累，由于其 通过晶状体内生物膜的相对不通透性，神经 组织和血管可能是这些并发症的原因。这个 这些并发症的主要原因可能是由于 山梨醇的积累，这是一种相对不透气的多元醇 通过生物膜，在组织中。渗透不平衡将会 导致水合增加、膜拉伸和功能障碍。醛糖 还原酶在NADPH的调节下将糖还原为多元醇。这 酶可能与糖性白内障有关，因为给药 醛糖还原酶抑制剂如山梨醇和阿司他丁对实验性 动物可以预防或显著延缓白内障的发生。我们发现了 不同组织中的醛糖还原酶可以被激活几倍 由葡萄糖-6-磷酸、葡萄糖和NADPH各10 Mu M组成。这个 未激活的酶被15 Mu M ADP、2，3-DPG或 3PGA。激活的酶不会被这些磷酸化的酶抑制 糖酵解中间体，对山梨醇的抑制作用更强 而阿司他丁则是未被激活的酶。它的动力学性质 从糖尿病患者组织中提纯的醛糖还原酶 从实验诱导的糖尿病和半乳糖血症的动物 将被研究并与血糖和多元醇水平相关。这个 醛酮还原酶将从人体组织中提纯为均一酶 将研究它们的动力学、结构和免疫学性质。 我们已将人红细胞中的醛糖还原酶纯化为均一酶。 并证明了糖尿病患者体内的酶活性 随着血糖的升高而增加。血糖水平较高 超过200 mg%时，所有的酶都保持激活状态。葡萄糖 和葡萄糖-6-P可能与醛糖还原酶共价结合，但 这些代谢物激活/失活该酶的机制是 不知道。所有缓蚀剂的结合特性和 因此，我们将对酶的活化机理进行研究。多肽图谱， 多肽结合处的N-端、C-端、氨基酸序列 中心将被确定。这些研究将有助于理解 醛糖还原酶在糖尿病并发症病理生理中的作用 最终应该会帮助调查人员设计出特定的抑制剂 醛糖还原酶。

Some of the diabetic complications such as cataractogenesis, retinopathy, neuropathy, and nephropathy are common among the persons suffering from diabetes for a period of time. Accumulation of sorbitol, due to its relative impermeability through biological membranes in the lens, neural tissues, and blood vessels may be the cause of these complications. The major cause of these complications could be the osmotic imbalance due to the accumulation of sorbitol, a polyol which is relatively impermeable through biological membranes, in the tissues. The osmotic imbalance will lead to increased hydration, membrane stretch, and dysfunction. Aldose reductase reduces sugars to polyols with the mediation of NADPH. This enzyme is probable involved in sugar cataracts, because administration of aldose reductase inhibitors such as sorbinil and alrestatin to experimental animals prevents or significantly delays cataractogenesis. We have found that aldose reductase from different tissues can be activated several fold by 10 Mu M each of glucose-6-phosphate, glucose, and NADPH. The unactivated enzyme is irreversibly inhibited by 15 Mu M ADP, 2,3-DPG, or 3PGA. The activated enzyme is not inhibited by these phosphorylated glycolytic intermediates and is more resistant to inhibition by sorbinil and alrestatin than is the unactivated enzyme. The kinetic properties of aldose reductase purified from the tissues of the diabetic subjects as well as from the animals with experimentally induced diabetes and galactosemia will be studied and correlated with blood sugar and polyol levels. The aldo-keto reductases will be purified to homogeneity from human tissues and their kinetic, structural, and immunological properties will be studied. We have purified aldose reductase from human erythrocytes to homogeneity and have demonstrated that in diabetic subjects the enzyme activity increases with increase in blood sugar. With blood glucose levels higher than 200 mg percent, all the enzyme remains in the activated form. Glucose and glucose-6-P probably covalently bind to aldose reductase but the mechanism of activation/inactivation of the enzyme by these metabolites is not known. The binding characteristics of all the inhibitors and the mechanism of enzyme activation will therefore be studied. Peptide mapping, N-terminal, C-terminal, amino acid sequence of the peptides at the binding centers will be determined. These studies will help in understanding the role of aldose reductase in the pathophysiology of diabetic complications and should eventually aid the investigators in devising specific inhibitors of aldose reductase.