Carmichael P L, Hipkiss A R
Institute of Cancer Research, Haddow Laboratories, Belmont, Sutton, Surrey, U.K.
Free Radic Res Commun. 1991;15(2):101-10. doi: 10.3109/10715769109049130.
The relative susceptibilities of lenticular proteins (alpha, beta and gamma-crystallins) and a number of proteins of non-lenticular origin, to hydroxyl radical-mediated peptide bond cleavage were compared. The non-lenticular proteins (bovine serum albumin, ovalbumin, alcohol dehydrogenase, lysozyme, thyroglobulin, beta-amylase, haemoglobin and carbonic anhydrase) were readily cleaved into acid-soluble fragments following 5 hours treatment with copper ions and hydrogen peroxide. In contrast the crystallins were almost totally unaffected by similar treatment. When alpha-crystallin was pre-treated with acid or cleaved into large fragments with cyanogen bromide it became susceptible to hydroxyl radical attack, yet heating the protein did not diminish its resistance. It is suggested that the resistance of alpha-crystallin to the copper/peroxide-mediated fragmentation may be dependent on the conformation of the protein.
比较了晶状体蛋白（α、β和γ-晶状体蛋白）以及一些非晶状体来源的蛋白质对羟基自由基介导的肽键断裂的相对敏感性。在用铜离子和过氧化氢处理5小时后，非晶状体蛋白（牛血清白蛋白、卵清蛋白、乙醇脱氢酶、溶菌酶、甲状腺球蛋白、β-淀粉酶、血红蛋白和碳酸酐酶）很容易被裂解为酸溶性片段。相比之下，晶状体蛋白几乎完全不受类似处理的影响。当α-晶状体蛋白用酸预处理或用溴化氰裂解为大片段时，它变得易于受到羟基自由基的攻击，然而加热该蛋白质并没有降低其抗性。有人提出，α-晶状体蛋白对铜/过氧化物介导的片段化的抗性可能取决于该蛋白质的构象。
