老化过程中α-晶体蛋白分子伴侣活性的变化

目的：研究老化过程中α-晶体蛋白的分子伴侣功能。方法：使用Sephacryl S-300HR分离幼年、中年和老年兔晶状体皮质和核α-晶体蛋白。测定α-晶体蛋白对加热(60℃)诱导过氧化氢酶(catalase，CAT）和β-晶体蛋白凝聚，果糖(37℃)和加热(60℃)诱导CAT失活的保护作用。结果：四种评估伴侣功能的方法有类似的结果。不同年龄兔晶状体皮质α-晶体蛋白的保护作用较核强，αH-晶体蛋白的伴侣功能均较αL-晶体蛋白降低；随着老化晶状体皮质αH-和αL-晶体蛋白的伴侣功能无显著性降低，但核αL-晶体蛋白伴侣功能的降低具有显著性。结论：晶状体核α-晶体蛋白年龄依赖性伴侣功能的降低，可以参与老年性白内障的形成。

Change of α-Crystallin Acting as Molecular Chaperone Activity with Ageing

PURPOSE: To evaluate the molecular chaperone function of alpha-crystallin with ageing. METHODS: alpha-Crystallin of newborn, adult and old rabbits lenses in both of cortex and nucleus were separated by chromatography on Sephacryl S-300HR. The protection of alpha-crystallin against thermal aggregation of catalase and beta L-crystallin (60 degrees C), inactivation of catalase by fructose(37 degrees C) and heat stress(60 degrees C) were measured spectrophotometrically. RESULTS: Protection of alpha-crystallin against aggregation and inactivation using four methods showed a similar pattern. The protective ability in cortex was greatly higher than in nucleus of different-aged lenses, and alpha H-crystallin was less than alpha L-crystallin in both cortex and nucleus. There was no statistically decrease with age of chaperone function of both alpha H-crystallin and alpha L-crystallin in the cortex, whereas alpha L-crystallin in the nucleus was compromised. CONCLUSION: alpha-Crystallin in the nucleus shows age-related decrease in chaperone function, which may be responsible for cataract formation.