Catalyzes several different glutathione-dependent reactions. Catalyzes the glutathione-dependent reduction of lipid hydroperoxides, such as 5-HPETE. Has glutathione transferase activity, toward xenobiotic electrophiles, such as 1-chloro-2, 4-dinitrobenzene (CDNB). Catalyzes also the conjugation of leukotriene A4 with reduced glutathione to form leukotriene C4 (LTC4). Involved in oxidative DNA damage induced by ER stress and anticancer agents by activating LTC4 biosynthetic machinery in nonimmune cells. glutathione + RX = a halide anion + an S-substituted glutathione + H(+) 1-chloro-2,4-dinitrobenzene + glutathione = 2,4-dinitrophenyl-S-glutathione + chloride + H(+) leukotriene C4 = glutathione + leukotriene A4 (5S)-hydroperoxy-(6E,8Z,11Z,14Z)-eicosatetraenoate + 2 glutathione = (5S)-hydroxy-(6E,8Z,11Z,14Z)-eicosatetraenoate + glutathione disulfide + H2O Each monomer binds on GSH molecule but only one subunit is catalytically active. Homotrimer. Belongs to the MAPEG family.