年龄相关性白内障α-晶状体蛋白的分子伴侣功能  

The Molecular Chaperone Function of α-crystallin in Age-related Cataract

作　　者：严宏[1] 惠延年[2] 王建伟[1] 

机构地区：[1]西安第四军医大学唐都医院眼科,西安710038 [2]西安第四军医大学西京医院眼科研究所,西安710032

出　　处：《眼科学报》2005年第4期156-160,共5页Eye Science

基　　金：中国人民解放军总后勤部留学回国人员基金资助项目(No:97H26).

摘　　要：目的:研究年龄相关性白内障α-晶状体蛋白的分子伴侣功能。方法:使用SephacrylS-300HR分离健康人透明的和年龄相关性白内障混浊的晶状体皮质和核的αL-晶状体蛋白。采用分光光度计测定αL-晶状体蛋白对过氧化氢酶(catalase,CAT)热凝聚的抑制作用。应用SDS-PAGE分析CAT与αL-晶状体蛋白在热凝聚实验中形成的复合物。结果:人αL-晶状体蛋白可特异性地抑制CAT热凝聚。透明晶状体皮质较核的抑制作用明显;白内障αL-晶状体蛋白的抑制作用明显下降,65岁以下与65岁以上、65岁以上白内障Ⅱ与Ⅳ级核之间αL-晶状体蛋白的抑制作用比较,差异均有显著性;65岁以下Ⅱ与Ⅳ级核之间比较,差异无显著性,但Ⅳ级核的抑制作用降低。SDS-PAGE显示热凝聚实验透明晶状体皮质αL-晶状体蛋白的20kDa带在加热后0、40min和2h可溶部分无显著减少,62kDa的CAT带含量逐渐减少。结论:人α-晶状体蛋白具有抑制CAT热凝聚的分子伴侣功能,白内障晶状体核的α-晶体蛋白具有年龄和混浊程度依赖性伴侣功能的降低,这在白内障形成过程中起重要作用。Purpose ： To evaluate the molecular chaperone function of α-crystallin in age-related cataract. Methods：αL-Crystallin of human clear and cataractous lenses in both the cortex and nucleus were separated by chromatography on Sephacryl S-300HR. The preventive effects of αL-crystallin on thermally induced aggregation of catalase were measured spectrophotometrically. The complex formation between a catalase and αL-crystallin during the aggregation experimental was detected by SDS-PAGE methods. Results：Human αL-crystallin specifically prevented catalase from thermal aggregation. Its preventive ability in cortex was greatly higher than that in nucleus of clear lenses. There was a remarkably decrease of preventive ability in cataractous lenses with statistical differences between the group under 65 years old and that over 65 years old, grade Ⅱ and grade Ⅳ in over 65 years group, whereas αL -crystallin showed no statistical change in under 65 years group but its preventive ability was diminished in grade Ⅳ. SDS-PAGE showed that the 20 kDa bands had no significant decrease in water-soluble portion after heating 0,40 mim and 2 h, whereas the 65 kD bands were increased.Conclusion ： α-Crystallin can function as a molecular chaperone by preventing thermal aggregation of catalase.A decrease in chaperone function from cataractous lenses has been showed in age-dependent and opacification-dependent fashion, which may play an important role in formation of cataract. Eye Science 2005;21：156-160.

关 键 词：Α-晶状体蛋白 分子伴侣 年龄相关性白内障 过氧化氢酶 

分 类 号：R776.1[医药卫生—眼科] R776[医药卫生—临床医学]