Glutathione Peroxidase 1 SelCys49Cys (human) (rec.)

Glutathione peroxidase 1 also known as GPx-1 is an enzyme that in humans is encoded by the GPX1 gene. Two alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. This gene encodes a member of the glutathione peroxidase family, consisting of eight known glutathione peroxidases (Gpx1-8) in humans. Mammalian Gpx1 (this gene), Gpx2, Gpx3, and Gpx4 have been shown to be selenium-containing enzymes, whereas Gpx6 is a selenoproten in humans with cysteine-containing homologues in rodents. In selenoproteins, the 21st amino acid selenocysteine is inserted in the nascent polypeptide chain during the process of translational recoding of the UGA stop codon. Glutathione peroxidase functions in the detoxification of hydrogen peroxide, and is one of the most important antioxidant enzymes in humans. It has been reported that the protein encoded by this gene protects from CD95-induced apoptosis in cultured breast cancer cells and inhibits 5-lipoxygenase in blood cells, and its overexpression delays endothelial cell growth and increases resistance to toxic challenges. This protein is one of only a few proteins known in higher vertebrates to contain selenocysteine, which occurs at the active site of glutathione peroxidase and is coded by the nonsense (stop) codon TGA.