In vitro synthesis of glutathione peroxidase from selenite Translational incorporation of selenocysteine

Wayne C. Hawkes, Al L. Tappel

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

The synthesis of glutathione peroxidase from [75Se]selenite was studied in slices and cell-free extracts from rat liver. The incorporation of [75Se]selenocysteine at the active site was detected by carboxymethylation and hydrolysis of partially purified glutathione peroxidase (glutathione:hydrogen peroxide oxidoreductase, EC 1.11.1.9) in the presence of [3H]selenocysteine and subsequent amino acid analysis. The synthesis of glutathione peroxidase in slices was inhibited by cycloheximide or puromycin and 75Se was incorporated from [75Se]selenite into free selenocysteine and selenocysteyl tRNA. Increasing concentrations of selenocystine caused a progressive dilution of the 75Se and a corresponding decrease in glutathione peroxidase labeling. In cell-free systems, [75Se]selenocysteyl tRNA was the best substrate for glutathione peroxidase synthesis. These results indicate the existence in rat liver of the de novo synthesis of free selenocysteine and a translational pathway of selenocysteine incorporation into glutathione peroxidase.

Original languageEnglish (US)
Pages (from-to)225-234
Number of pages10
JournalBBA - Gene Structure and Expression
Volume739
Issue number2
DOIs
StatePublished - Mar 10 1983

Keywords

  • Glutathione peroxidase
  • Selenocysteine, Selenite, Protein synthesis
  • tRNA

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Genetics
  • Structural Biology
  • Medicine(all)

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