羟基自由基积累meta标记,ortho-tyrosine洪流的镜头和多巴是伴随着较低的蛋白质和苯丙氨酸含量水溶性的阶段。

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Molnar GA,所V,比罗Z, Ludany,瓦格纳Z,维

羟基自由基积累meta标记,ortho-tyrosine洪流的镜头和多巴是伴随着较低的蛋白质和苯丙氨酸含量水溶性的阶段。

自由·拉迪奇研究》2005年12月,39 (12):1359 - 66。

PubMed ID
16298866 (在PubMed
]
文摘

晶状体蛋白的转录后修饰起到至关重要的作用在白内障的形成老化。我们的研究的目的是分析蛋白质组成的洪流的镜头通过电泳和高效液相色谱(HPLC)方法。样本获得从白内障囊外白内障手术由乳化技术后2型糖尿病患者(DM猫,n = 22)和非糖尿病白内障患者(non-DM猫,n = 20),而非糖尿病non-cataractous镜头从尸体的眼睛获得担任控制(来讲,n = 17)。镜头片段被离心源自于手术中。样品均质在缓冲中含有蛋白酶抑制剂。可溶性和不可溶性蛋白质分数被离心分离。电泳研究进行根据Laemmli等量的蛋白质,紧随其后的是银色的强化。氧化氨基酸和检的样品也分析了高效液相色谱在酸水解蛋白质。代表了我们的研究结果表明,可溶性蛋白质显著降低部分总蛋白质含量的洪流的镜头与对照组(相比来讲,71.25%;non-DM猫,32.00%; DM CAT, 33.15%; p < 0.05 vs CONTR for both). Among the proteins, the crystallin-like proteins with low-molecular weight can be found both in the soluble and insoluble fractions, and high-molecular weight aggregates were found mainly in the total homogenates. In our HPLC analysis, oxidatively modified derivatives of phenylalanine were detected in cataractous samples. We found higher levels of m-Tyr, o-Tyr and DOPA in the total homogenates of cataractous samples compared to the supernatants. In all three groups, the median Phe/protein ratio of the total homogenates was also higher than that of the supernatants (total homogenates vs supernatants, in the CONTR group 1102 vs 633 micromol/g, in the DM CAT group 1187 vs 382 micromol/g and in the non-DM CAT group 967 vs 252 micromol/g; p < 0.05 for all). In our study we found that oxidized amino acids accumulate in cataractous lenses, regardless of the origin of the cataract. The accumulation of the oxidized amino acids probably results from oxidation of Phe residues of the non-water soluble lens proteins. We found the presence of high-molecular weight protein aggregates in cataractous total homogenates, and a decrease of protein concentration in the water-soluble phase of cataractous lenses. The oxidation of lens proteins and the oxidative modification of Phe residues in key positions may lead to an altered interaction between protein and water molecules and thus contribute to lens opacification.

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