Age-related changes in human lens crystallins identified by HPLC and mass spectrometry
Age-related changes in human lens crystallins identified by HPLC and mass spectrometry
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DOI：
10.1006/exer.1998.0482
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发表时间：
1998-07-01
影响因子：
3.4
通讯作者：
Smith, JB
中科院分区：
文献类型：
--
作者：
Ma, ZX;Hanson, SRA;Smith, JB
人晶状体水溶性晶体蛋白的分析。年龄从32周胎儿到55岁已经导致鉴定出构成透镜的蛋白质的主要修饰。这些修改被确定的蛋白质的质量后，通过凝胶过滤和反相高效液相色谱分离的蛋白质，通过电喷雾电离质谱法。对从水溶性部分分离的所有蛋白质的检查表明，导致透镜晶体蛋白分子量显著改变的主要年龄相关修饰包括β B1、β A3和β A1的N-末端截短以及α-晶体蛋白的部分磷酸化和C-末端降解。β B1，β A3和β A1的N-末端降解在不到一岁的人类晶状体中是明显的，并且这些截短蛋白质的比例随着年龄的增长而增加。从胎儿到3岁的透镜，α A-和α B-晶状体蛋白的磷酸化增加，但不随进一步的老化而改变。在旧镜片中发现了表明α-晶状体蛋白C-末端截短的次要组分。与β B1，β A3和β B2相比，β B1和β A3都是一种生物。β A1，α A、α B、β B2、β A4、γ S、γ C和γ D的主要物质的质量不随老化而变化。这表明这些晶体蛋白的主要修饰仅限于脱酰胺和可能的分子内二硫键。这些数据与随附手稿中的数据相结合，确定脱酰胺是一种常见的修饰，因为脱酰胺仅引起一个道尔顿的质量变化，是唯一与随附论文的二维凝胶中未检测到分子量变化和观察到酸度增加一致的修饰。其他年龄相关变化包括β B3（M-r 24224）（胎儿透镜的主要成分）降低，在3岁以上的晶状体中未检测到，以及α B：α A和γ S：γ C比值增加。(C)北京：科学出版社.
Analysis of water-soluble crystallins from human lenses. ages 32 week fetal to 55 years has led to identification of the major modifications of the proteins comprising the lens. These modifications were identified by the masses of the proteins determined by electrospray ionization mass spectrometry after the proteins were separated by gel filtration and reversed phase high performance liquid chromatography. Examination of all the proteins isolated from the water soluble portion demonstrated that the major age-related modifications causing significant alteration in the molecular weights of the lens crystallins include truncation of the N-termini of beta B1, beta A3 and beta A1 and partial phosphorylation and C-terminal degradation of alpha-crystallins. N-terminal degradation of beta B1, beta A3 and beta A1 was evident in human lenses less than one year old, and the proportion of these truncated proteins became greater with age. Phosphorylation of alpha A- and alpha B-crystallins increased from the fetal to the 3 year old lens, but did not change with further aging. Minor components indicating truncation of the C-termini of a-crystallins were found in older lenses. In contrast to beta B1, beta A3 and. beta A1, the masses of the major species of alpha A, alpha B, beta B2, beta A4, gamma S, gamma C, and gamma D did not change with aging. This suggested that the major modifications to these crystallins are limited to deamidation and possibly intra-molecular disulfide bonds. These data, in conjunction with the data in the accompanying manuscript, established deamidation as a common modification, since deamidation, which causes only a one dalton change in mass, is the only modification that is consistent with the absence of a detectable change in molecular weight and the observed increased acidity demonstrated in the two-dimensional gels of the accompanying paper. Other age related changes included a decrease in beta B3 (M-r 24224), a major component of the fetal lens, which was not detected in lenses older than 3 years, and increases in the ratios of alpha B:alpha A and gamma S:gamma C. (C) 1998 Academic Press.