 The antioxidant enzyme glutathione peroxidase 4 (GPx4) belongs to the family of glutathione peroxidases, which consists of 8 known mammalian isoenzymes (GPx1-8).Gpx4 catalyzes the reduction of hydrogen peroxide, organic hydroperoxides, and lipid peroxides at the expense of reduced glutathione and functions in the protection of cells against oxidative stress.The oxidized form of glutathione (glutathione disulfide), which is generated during the reduction of hydroperoxides by GPx4, is recycled by glutathione reductase and NADPH/H+.