Oxidative damage to lysozyme by the hydroxyl radical: comparative effects of scavengers

Elisabeth Franzini, Hassan Sellak, Jacques Hakim, Catherine Pasquier

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

The hydroxyl radical (OH.) is a highly-damaging reactive oxygen species, given its high reactivity and the consequent generation of secondary free radicals. This study was aimed at determining the qualitative and quantitative aspects of OH. scavenging by pentoxifylline (Ptx, a methylxanthine), uric acid and thymine on the OH./mol lysozyme; moreover, SDS-PAGE showed a loss of native lysozyme (14.4 kDa), the presence of dimer and trimer aggregates and characteristic fragmentation. Tryptophan fluorescence was lost before aggregation became detectable in terms of bityrosine formation. Increasing concentrations of OH. scavengers gave increasing protection of lysozyme activity. Although all three compounds scavenge OH. with high rate constants, their effects were different: uric acid and Ptx prevented aggregation and preserved enzyme activity, whereas thymine preserved activity but did not prevent aggregation. These differences appear to be related to the formation of reducing secondary radicals, underlining the importance of this mechanism in the effects of scavengers.

Original languageEnglish (US)
Pages (from-to)11-17
Number of pages7
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Volume1203
Issue number1
DOIs
StatePublished - Nov 10 1993

Keywords

  • Free radical
  • Hydroxyl radical
  • Lysozyme
  • Radiolysis

ASJC Scopus subject areas

  • Structural Biology
  • Biophysics
  • Biochemistry
  • Molecular Biology

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