Glutathione peroxidase

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glutathione peroxidase 1
Identifiers
Symbol	GPX1
HUGO	4553
Entrez	2876
OMIM	138320
RefSeq	NM_000581
UniProt	P07203
Other data
EC number	1.11.1.9
Locus	Chr. 3 p21.3

glutathione peroxidase 3 (plasma)
Identifiers
Symbol	GPX3
HUGO	4555
Entrez	2878
OMIM	138321
RefSeq	NM_002084
UniProt	P22352
Other data
EC number	1.11.1.9
Locus	Chr. 5 q23

glutathione peroxidase 5 (epididymal androgen-related protein)
Identifiers
Symbol	GPX5
HUGO	4557
Entrez	2880
OMIM	603435
RefSeq	NM_001509
UniProt	O75715
Other data
EC number	1.11.1.9
Locus	Chr. 6 p21.32

glutathione peroxidase 6 (olfactory)
Identifiers
Symbol	GPX6
HUGO	4558
Entrez	257202
OMIM	607913
RefSeq	NM_182701
UniProt	P59796
Other data
EC number	1.11.1.9
Locus	Chr. 6 p21

Glutathione peroxidase (PDB 1GP1, EC 1.11.1.9) is the general name of an enzyme family with peroxidase activity whose main biological role is to protect the organism from oxidative damage. The biochemical function of glutathione peroxidase is to reduce lipid hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water. There are several isozymes encoded by different genes, which vary in celullar location and substrate specificity. Glutathione peroxidase 1 is the most abundant version, found in the cytoplasm of nearly all mammalian tissues, whose preferred substrate is hydrogen peroxide. An example reaction that glutathione peroxidase catalyzes is:

2GSH + H₂O₂ → GSSG + 2H₂O,

where GSH represents reduced monomeric glutathione, and GSSG represents glutathione disulphide. 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. Mice genetically engineered to lack glutathione peroxidase 1 (Gpx1 knockout mice) are phenotypically normal, indicating that this enzyme is not critical for life. However, glutathione peroxidase 4 knockout mice (Gpx4 knockout) die during early embryonic development.

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

Glutathione peroxidase was discovered in 1957 by Gordon C. Mills. See Journal of Biological Chemistry 229:189-97.1957.