维生素C在晶体蛋白光氧化中的作用及其机制  

Effects of ascorbic acid on the photo-oxidation of crystallin

作　　者：吴开力[1,2] 潘苏华[1,2] 李绍珍[1,2] 

机构地区：[1]广州中山医科大学 [2]中山眼科中心

出　　处：《眼科》1999年第3期161-164,共4页Ophthalmology in China

基　　金：广东省自然科学基金

摘　　要：目的：观察维生素Ｃ（ＡＳＡ）在晶体蛋白发生光氧化时的作用及其机制。方法：牛晶体蛋白溶液在加入或不加入ＡＳＡ时，于５天内共接受２００ｍＪ／ｃｍ２紫外线Ｂ（ＵＶＢ）照射，接着在３７℃继续孵育至第３周，然后测定晶体蛋白的非色氨酸荧光、游离巯基和进行蛋白电泳分析。结果：ＡＳＡ在溶液中易被氧化，蛋白溶液中加入ＡＳＡ促使晶体蛋白的非色氨酸荧光产生明显增强，导致非二硫键聚合形成，对晶体蛋白的游离巯基减少有保护作用。有ＡＳＡ时，ＵＶＢ照射更易导致晶体蛋白形成非二硫键聚合。结论：体外溶液中的ＡＳＡ易与晶体蛋白发生糖化作用，同时作为抗氧化剂能保护晶体蛋白的游离巯基不被氧化。In order to explore the effects of ascorbic acis(ASA)on the photo-oxidation of crystallin.Bovine crystalline solution mixed with or without ASA were irradiated with 200mJ/cm 2 of UVB,and then incubated at 37℃ for three weeks.Measurement of non-tryptophan fluorescence,free sulfhydryl of protein and SDS-polyacrylamide electrophoresis were performed to compare with the alteration of lens protein under different treatments.The results showed that ASA is easy to be oxidized in solution.It promotes the production of the non-tryptophan fluorescence and the aggregation of crystallins.Irradiating the mixture of lens protein and ASA with UVB can result in obvious aggregation of crystallins through mainly non-disulfide bond.ASA can protect protein sulfhydryl against photo-oxidation.The present study suggests that ASA is easy to induce the glycation of crystallins in solution,and as an antioxidant,it can prevent the oxidation of protein sulfhydryls.

关 键 词：抗坏血酸 晶体蛋白 光氧化 紫外线 眼 白内障 

分 类 号：R776.102[医药卫生—眼科] R339.141[医药卫生—临床医学]