Mitochondrial thioltransferase (glutaredoxin 2) has GSH-dependent and thioredoxin reductase-dependent peroxidase activities in vitro and in lens epithelial cells

M. Rohan Fernando, Joel M. Lechner, Stefan Löfgren, Vadim N. Gladyshev, Marjorie F. Lou

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

Thioltransferase (or Grx) belongs to the oxidoreductase family and is known to regulate redox homeostasis in cells. Mitochondrial Grx2 is a recent discovery, but its function is largely unknown. In this study we investigate Grx2 function by examining its potential peroxidase activity using lens epithelial cells (LEC). cDNA for human and mouse Grx2 was cloned into pET21d(+) vector and used to produce respective recombinant Grx2 for kinetic studies. cDNA for human Grx2 was transfected into human LEC and used for in vivo studies. Both human and mouse Grx2 showed glutathione (GSH)-dependent and thioredoxin reductase (TR)-dependent peroxidase activity. The catalytic efficiency of human and mouse Grx2 was lower than that of glutathione peroxidases (2.5 and 0.8 × 104 s-1M-1, respectively), but comparable with TR-dependent peroxiredoxins (16.5 and 2.7 × 104 s-1M-1, respectively). TR-dependent peroxidase activity increased 2-fold in the transfected cells and was completely abolished by addition of anti-Grx2 antibody (Ab). Flow cytometry (FACS) analysis and confocal microscopy revealed that cells preloaded with pure Grx2 detoxified peroxides more efficiently. Grx2 over-expression protected cells against H 2O2-mediated disruption of mitochondrial transmembrane potential. These results suggest that Grx2 has a novel function as a peroxidase, accepting electrons both from GSH and TR. This unique property may play a role in protecting the mitochondria from oxidative damage.

Original languageEnglish (US)
Pages (from-to)E2240-E2248
JournalFASEB Journal
Volume20
Issue number14
DOIs
StatePublished - Dec 1 2006

Fingerprint

Glutaredoxins
Thioredoxin-Disulfide Reductase
Peroxidase
Lenses
Glutathione
Epithelial Cells
Complementary DNA
Peroxiredoxins
Mitochondria
Flow cytometry
Confocal microscopy
Peroxides
Glutathione Peroxidase
Oxidoreductases
Confocal Microscopy
Membrane Potentials
Oxidation-Reduction
Anti-Idiotypic Antibodies
Flow Cytometry
Homeostasis

Keywords

  • Antioxidant enzymes
  • Oxidative stress
  • Peroxide removal
  • Peroxiredoxins

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

Cite this

Mitochondrial thioltransferase (glutaredoxin 2) has GSH-dependent and thioredoxin reductase-dependent peroxidase activities in vitro and in lens epithelial cells. / Fernando, M. Rohan; Lechner, Joel M.; Löfgren, Stefan; Gladyshev, Vadim N.; Lou, Marjorie F.

In: FASEB Journal, Vol. 20, No. 14, 01.12.2006, p. E2240-E2248.

Research output: Contribution to journalArticle

Fernando, M. Rohan ; Lechner, Joel M. ; Löfgren, Stefan ; Gladyshev, Vadim N. ; Lou, Marjorie F. / Mitochondrial thioltransferase (glutaredoxin 2) has GSH-dependent and thioredoxin reductase-dependent peroxidase activities in vitro and in lens epithelial cells. In: FASEB Journal. 2006 ; Vol. 20, No. 14. pp. E2240-E2248.
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