人γ-晶体蛋白的研究:Ⅴ.胚胎晶体γ_1-、γ_3-晶体蛋白在体外的非酶糖化作用

Study on Human γ-Crystallins:V . Non-Enzymatic Glycation of Fetal Lensγ_1 and γ_3-Crystallins in Vitro

目的:比较由葡萄糖和果糖诱发不同的人胚胎γ-晶体蛋白的非酶糖化作用。方法:用Sephadex凝胶层析方法从人类胚胎晶体中分离出γ_1和γ_3-晶体蛋白,将这些γ-晶体蛋白与葡萄糖或果糖37℃下培养20天,γ-晶体蛋白产生非酶糖化作用,混浊和块状沉淀出现,还观察到SDS—PAGE图谱的变化和蓝色荧光产物。结果:虽然两种γ-晶体蛋白出现相类似的变化。但在早期阶段(3天)γ_1-晶体蛋白更容易产生聚合和不溶解。SDS—PAGE显示有聚合物产生,这些都是通过二硫键和非二硫键交联以及肽键的降解而形成。γ_3-晶体蛋白溶液糖化作用后,蓝色荧光增加。果糖与γ-晶体蛋白的糖化作用比葡萄糖更明显(如:聚合、降解、产生蓝色荧光)。结论:人类胚胎γ_1和γ_3-晶体蛋白对非酶糖化作用是敏感的,程度亦有不同(γ_1>γ_3),果糖的作用比葡萄糖强。眼科学报 1995;

Purpose: To compare the non-enzymatic glycation of different human fetal 7-crys-tallins induced by glucose and fructose.Methods: γ1- and γ2-crystallin were separated by the Sephadex gel chromatogra-phy from human fetal lenses. The non-enzymatic glycations of these γ-crystallins were conducted by incubating with glucose or fructose at 37℃ for 20 days. The opacity and pellet formation as well as changes on SDS-polyacrymide gel elec-trophoresis (SDS-PAGE) pattern and blue fluorescence production were observed.Results: Although the two γ-crystallins displayed similar alterations, γ1-crystallin was easier to produce aggregation and insolublization in early stage (i. e. 3 days). SDS-PAGE showed that there were aggregates, formed through disulfide and non-disulfide cross-links, and degraded peptides produced. The blue fluorescence increased in glycated r3-crystalline solution. Fructose had more significant effects (i.e. aggregation, degradation, producing blue fluorescence) on r-crystallins as compared with glucose.Conclusion: Human fetal γ1-and γ3-crystallins are sensitive, at different extent(γ1 >γ3), to response to non-enzymatic glycation, and fructose has stronger effect than glucose on the glycation. Eye Science 1995; 11: 197-201.