Structural changes in bovine lens crystallins induced by ascorbate, metal, and oxygen |
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Authors: | D Garland J S Zigler J Kinoshita |
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Abstract: | 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. |
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