Glutathione peroxidase (, ) is a peroxidase found in the erythrocytes of mammals that helps prevent lipid peroxidation of the cell membrane. The function of glutathione peroxidase, therefore, is to reduce lipid hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water. An example reaction that glutathione peroxidase catalyzes is:

2GSH + H₂O₂ → GSSG + 2H₂O,

where GSH represents reduced monomeric glutathione, and GSSG represents oxidized glutathione. Glutathione reductase then reduces the oxidized glutathione to complete the cycle:

GSSG + NADPH + H⁺ → 2 GSH + NADP⁺.

Glutathione peroxidase is a selenium-containing tetrameric glycoprotein, that is, a molecule with four selenocysteine amino acid residues. As the integrity of the cellular and subcellular membranes depends heavily on glutathione peroxidase, the antioxidative protective system of glutathione peroxidase itself depends heavily on the presence of selenium.

The bovine erythrocyte enzyme has a molecular weight of 84 kDa.

See also

• Glutathione reductase

EC 1.11.1 | Antioxidants

Glutathionperoxidase | Glutathion peroxidáza