Cerami A, Stevens V J, Monnier V M
Metabolism. 1979 Apr;28(4 Suppl 1):431-7. doi: 10.1016/0026-0495(79)90051-9.
The increased level of the glycosylated hemoglobin (hemoglobin A1c) in the diabetic patient has proved to be an interesting clue to understanding the biochemical basis of the sequelae of diabetes. This minor hemoglobin, which arises as nonenzymatic postsynthetic addition of glucose to hemoglobin A, acts as an indicator molecule for the glucose environment over a 3-5-wk period prior to measurement. Reasoning that a similar glycosylation reaction could be occurring with other body proteins, we have studied the ocular lens. The lens, like the erythrocyte, is not dependent on insulin for glucose concentration in the extracellular milieu that would be elevated in the diabetic state. These studies have revealed that a high glucose in vivo or an increased glucose or glucose-6-phosphate concentration in vitro leads to the glycosylation of epsilon-amino groups of lysine residues in bovine and rat lens crystallins. This glycosylation imparts an increased susceptibility of the crystallins to sulfhydryl oxidation. Disulfide crosslinks result in the formation of high molecular weight aggregates and an opalescence of the crystallin solutions.
糖尿病患者糖化血红蛋白（血红蛋白A1c）水平的升高已被证明是理解糖尿病后遗症生化基础的一个有趣线索。这种次要的血红蛋白是葡萄糖在合成后非酶促地添加到血红蛋白A上形成的，在测量前的3 - 5周内，它作为葡萄糖环境的指示分子。基于其他身体蛋白质可能发生类似糖基化反应的推测，我们对晶状体进行了研究。晶状体与红细胞一样，在细胞外环境中的葡萄糖浓度方面不依赖胰岛素，而在糖尿病状态下该浓度会升高。这些研究表明，体内高血糖或体外葡萄糖或葡萄糖 - 6 - 磷酸浓度升高会导致牛和大鼠晶状体晶状体蛋白中赖氨酸残基的ε - 氨基糖基化。这种糖基化使晶状体蛋白对巯基氧化的敏感性增加。二硫键交联导致形成高分子量聚集体以及晶状体蛋白溶液出现乳光现象。
