Inactivation of glutathione peroxidase by superoxide radical

Janice Blum, Irwin Fridovich

Research output: Contribution to journalArticle

470 Scopus citations

Abstract

The selenium-containing glutathione peroxidase, when in its active reduced form, was inactivated during exposure to the xanthine oxidase reaction. Superoxide dismutase completely prevented this inactivation, whereas catalase, hydroxyl radical scavengers, or chelators did not, indicating that {A figure is presented} was the responsible agent. Conversion of GSH peroxidase to its oxidized form, by exposure to hydroperoxides, rendered it insensitive toward {A figure is presented}. The oxidized enzyme regained susceptibility toward inactivation by {A figure is presented} when reduced with GSH. The inactivation by {A figure is presented} could be reversed by GSH; however, sequential exposure to {A figure is presented} and then hydroperoxides caused irreversible inactivation. Reactivity toward CN- has been used as a measure of the oxidized form of GSH peroxidase, whereas reactivity toward iodoacetate has been taken as an indicator of the reduced form. By these criteria both {A figure is presented} and hydroperoxides convert the reduced form to oxidized forms. A mechanism involving oxidation of the selenocysteine residue at the active site has been proposed to account for these observations.

Original languageEnglish (US)
Pages (from-to)500-508
Number of pages9
JournalArchives of Biochemistry and Biophysics
Volume240
Issue number2
DOIs
StatePublished - Aug 1 1985
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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