Oxidative modification of lens crystallins by H2O2 and chelated iron

J. Samuel Zigler, Qing Ling Huang, Xin yu Du

Research output: Contribution to journalArticlepeer-review

Abstract

Crystallins are the soluble structural proteins that constitute approximately 90% of the dry mass of the eye lens. The present study attempts to elucidate possible mechanisms whereby the H2O2 present in the eye could contribute to the oxidative modification of lens crystallins. The data indicate that exposure of solutions of crystallins to H2O2 and EDTA-chelated iron leads to covalent crosslinking of polypeptides, loss of intrinsic protein fluorescence, and the generation of a novel flurophor emitting in the 420 nm range. These changes closely mimic oxidative modifications that occur in lens proteins in vivo. Exposure of the proteins to H2O2 in the absence of chelated iron failed to generate detectable levels of these modifications. These findings are contrasted with earlier studies of lenses in organ culture where H2O2 alone produced marked damage while the further addition of chelated iron protected the lenses from oxidation.

Original languageEnglish (US)
Pages (from-to)499-505
Number of pages7
JournalFree Radical Biology and Medicine
Volume7
Issue number5
DOIs
StatePublished - 1989

Keywords

  • Fenton reaction
  • Free radicals
  • HO
  • Lens crystallins
  • Oxidation
  • Protein modification
  • hydroxyl radical

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)

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