Conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles. Protects against the thiol-mediated metal-catalyzed oxidative inactivation of enzymes. Involved in the formation of glutathione conjugates of both prostaglandin A2 (PGA2) and prostaglandin J2 (PGJ2). Participates in the formation of novel hepoxilin regioisomers (By similarity). glutathione + RX = a halide anion + an S-substituted glutathione + H(+) glutathione + prostaglandin A2 = prostaglandin A2-S-(R)-glutathione glutathione + prostaglandin J2 = prostaglandin J2-S-(R)-glutathione glutathione + prostaglandin J2 = prostaglandin J2-S-(S)-glutathione glutathione + prostaglandin A2 = prostaglandin A2-S-(S)-glutathione 11(S)-hydroxy-14(S),15(S)-epoxy-(5Z,8Z,12E)-eicosatrienoate + glutathione = (11S,15S)-dihydroxy-14(R)-S-glutathionyl-(5Z,8Z,12E)-eicosatrienoate Homodimer. Belongs to the GST superfamily. Mu family.