GPX4 Protein, Human (U73S, His)

GPX4 is an essential antioxidant peroxidase that directly reduces phospholipid hydroperoxides, including those incorporated in membranes and lipoproteins (By similarity). It also reduces cholesterol hydroperoxide and thymine hydroperoxide (By similarity), playing a key role in protecting cells from oxidative damage by preventing membrane lipid peroxidation (By similarity). GPX4 is required to inhibit ferroptosis, a non-apoptotic cell death caused by iron-dependent accumulation of lipid reactive oxygen species (PubMed:24439385). The presence of selenocysteine (Sec) versus cysteine (Cys) at the active site is critical for life, as it provides resistance to overoxidation and prevents ferroptosis (By similarity). Sec is also essential for the survival of parvalbumin-positive interneurons, thereby preventing fatal epileptic seizures (By similarity). GPX4 may protect cells from the toxicity of ingested lipid hydroperoxides (By similarity) and is indispensable for normal sperm development, male fertility (By similarity), and photoreceptor cell maturation and survival (By similarity). In T-cell responses to viral and parasitic infections, GPX4 prevents ferroptosis and supports T-cell expansion (By similarity). Additionally, it functions as a glutathione peroxidase in platelets during arachidonic acid metabolism (PubMed:11115402) and reduces hydroperoxy ester lipids formed by 15-lipoxygenase, downregulating the cellular 15-lipoxygenase pathway (By similarity). GPX4 can also reduce fatty acid-derived hydroperoxides (PubMed:11115402, PubMed:36608588) and small soluble hydroperoxides such as H2O2, cumene hydroperoxide, and tert-butyl hydroperoxide (PubMed:17630701, PubMed:36608588).