title: Aspartic acid racemization in heavy molecular weight crystallins and water insoluble protein from normal human lenses and cataracts.
abstract: High D/L aspartic acid ratios are observed in heavy molecular weight aggregates and in water-insoluble protein extracted from whole lenses and nuclear and cortical regions. Purified alpha-, beta-, and gamma-crystallins have low D/L ratios. Fractionation of urea-solubilized material from the water-insoluble protein yields four molecular weight classes of proteins. Fractions representing crosslinked material or apparently degraded products have high D/L ratios. Racemization within lens proteins may contribute to formation of the water-insoluble fraction seen in aging lenses and cataracts.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging; D001224:Aspartic Acid / Q000378:metabolism; D002386:Cataract / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D003459:Crystallins / Q000378:metabolism; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007908:Lens, Crystalline / Q000378:metabolism / Q000648:ultrastructure; D008875:Middle Aged; D008970:Molecular Weight; D011487:Protein Conformation; D012995:Solubility; D013237:Stereoisomerism
chemical_list: D003459:Crystallins; D001224:Aspartic Acid
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