Lampi K J, Ma Z, Hanson S R, Azuma M, Shih M, Shearer T R, Smith D L, Smith J B, David L L
Department of Oral Molecular Biology, Oregon Health Sciences University, Portland 97201, USA.
Exp Eye Res. 1998 Jul;67(1):31-43. doi: 10.1006/exer.1998.0481.
The purpose of this study was to identify the major protein components in adult human lenses and to analyse the specific age-related changes in these proteins using two-dimensional electrophoresis, Edman sequencing, and in conjunction with the data in the accompanying manuscript, mass spectrometry. The majority of changes in the two-dimensional electrophoretic pattern of lens proteins occurred prior to 17 years of age, and included a decrease in proteins migrating to the original positions of beta B1, beta B3, beta A3, gamma C and gamma D, and the appearance of many new species with apparent molecular weights on two-dimensional electrophoretic gels similar to beta B2 and gamma S, but having more acidic pIs. These proteins were identified as deamidated forms of beta B1 and beta A3/A1 missing portions of their N-terminal extensions. With the exception of alpha B, deamidation was detected in all crystallin species. These data indicated that a major fraction of the water-soluble protein of the adult human lens is composed of truncated beta B1 and beta A3/A1 crystallins, and that nearly all human crystallins, including the, beta-crystallins, are susceptible to deamidation. The results also provided the most detailed map to date of the identities of protein species on two-dimensional electrophoresis gels of adult human lenses.
本研究的目的是鉴定成人晶状体中的主要蛋白质成分，并使用二维电泳、埃德曼测序以及结合随附手稿中的数据和质谱分析这些蛋白质中与年龄相关的特定变化。晶状体蛋白质二维电泳图谱中的大多数变化发生在17岁之前，包括迁移至βB1、βB3、βA3、γC和γD原始位置的蛋白质减少，以及在二维电泳凝胶上出现许多新的蛋白质条带，其表观分子量与βB2和γS相似，但具有更酸性的等电点。这些蛋白质被鉴定为βB1和βA3/A1的脱酰胺形式，缺失其N端延伸部分。除αB外，在所有晶状体蛋白中均检测到脱酰胺作用。这些数据表明，成人晶状体中大部分水溶性蛋白质由截短的βB1和βA3/A1晶状体蛋白组成，并且几乎所有人类晶状体蛋白，包括β-晶状体蛋白，都易受脱酰胺作用影响。该结果还提供了迄今为止成人晶状体二维电泳凝胶上蛋白质种类身份的最详细图谱。
