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Abstract
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The primary biological function of the family of peroxidase-active enzymes known as glutathione peroxidases is to protect living things from oxidative damage. The effects of H2O2 are counteracted by glutathione peroxidase [1]. Due to the sensitivity of cellular lipid molecules to free radicals and the reaction that results in the production of lipid peroxide, glutathione peroxidase also inhibits the creation of free radicals by converting peroxides to alcohol. Many isoenzymes of glutathione peroxidase are produced by various genes [2].
GPXs (EC 1.11.1.9 for traditional glutathione peroxidase and EC 1.11.1.12, phospholipid hydroperoxide glutathione peroxidase) vary dramatically both for the oxidizing peroxides and the reducing substrates [3]. They catalyze the oxidation of reduced glutathione (GSH, -Glu-Cys-Gly) or thioredoxin (TRX) and the reduction of H2O2 or organic hydroperoxides to water or corresponding alcohols [4]. The first GPX was found in erythrocytes [5], but subsequent research has identified other GPXs in the estimated eukaryotic species. The highly reactive selenocysteine (SeCys) residue is present in the active region of certain GPX isoenzymes whereas Cys is present in others [6]. Animals' ROS-processing systems are thought to be mostly composed of the seleno- or nonseleno GPXs [7].
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