Purification and properties of glutathione peroxidase from human placenta

Y. C. Awasthi, D. D. Dao, A. K. Lal, S. K. Srivastava

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

Glutathione peroxidase (glutathione-H2O2 oxidoreductase; EC 1.11.1.9) was purified to homogeneity from human placenta by using (NH4)2SO4 precipitation, ion-exchange chromatography, Sephadex gel filtration and preparative polyacrylamide-disc-gel electrophoresis. Glutathione peroxidase from human placenta is a tetramer, having 4g-atoms of selenium/mol of protein. The molecular weight of the enzyme is about 85,000 with a subunit size of about 22,000. Kinetic properties of the enzyme are described. On incubation with cyanide, glutathione peroxidase is completely and irreversibly inactivated and selenium is released as a low-molecular-weight fragment. Reduced glutathione, β-mercaptoethanol and dithiothreitol protect the enzyme from inactivation by cyanide and the release of selenium. Properties of human placental glutathione peroxidase are similar to those of isoenzyme A reported earlier by us from human erythrocytes. The presence of isoenzyme B, reported earlier by us in human erythrocytes, was not detected in placenta. Also selenium-independent glutathione peroxidase (isoenzyme II), which is specific for cumene hydroperoxide, was not present in human placenta.

Original languageEnglish (US)
Pages (from-to)471-476
Number of pages6
JournalBiochemical Journal
Volume177
Issue number2
DOIs
StatePublished - 1979

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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