Could play a major role in protecting mammals from the toxicity of ingested organic hydroperoxides. Tert-butyl hydroperoxide, cumene hydroperoxide and linoleic acid hydroperoxide but not phosphatidycholine hydroperoxide, can act as acceptors. a hydroperoxide + 2 glutathione = an alcohol + glutathione disulfide + H2O 2 glutathione + H2O2 = glutathione disulfide + 2 H2O 2 glutathione + tert-butyl hydroperoxide = glutathione disulfide + H2O + tert-butanol cumene hydroperoxide + 2 glutathione = 2-phenylpropan-2-ol + glutathione disulfide + H2O Homotetramer. Exclusively expressed in the stomach and small intestine. Belongs to the glutathione peroxidase family.