Structural changes in bovine lens crystallins induced by ascorbate, metal, and oxygen.
Ascorbate, Fe3+, or Cu2+ and oxygen induced the oxidation of bovine lens crystallins. The modifications mimicked those that occur in the lens with aging. The modifications included the formation of nondisulfide crosslinks in alpha- and beta H-crystallin and the cleavage of alpha-, beta H-, and the low molecular weight crystallin fractions. In all three fractions, there was a loss of the more basic protein species and an increase in the more acidic species. Nontryptophan fluorescence with emission spectra between 400 and 500 nm was produced in beta H-crystallin. Cu2+ was less effective than Fe3+ in catalyzing the modification of beta H- and gamma-crystallin. Both metal ions were equally effective in catalyzing the modification of alpha-crystallin.
D000375:Aging / Q000378:metabolism; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003459:Crystallins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D007525:Isoelectric Focusing; D008670:Metals / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D013050:Spectrometry, Fluorescence
D003459:Crystallins; D008670:Metals; D001205:Ascorbic Acid; D010100:Oxygen