Conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles. Involved in the formation of glutathione conjugates of both prostaglandin A2 (PGA2) and prostaglandin J2 (PGJ2) (PubMed:9084911). Participates in the formation of novel hepoxilin regioisomers (PubMed:21046276). 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. Liver (at protein level). There are two alleles; GSTM1A and GSTM1B which differ in position 173. The sequence shown is that of allele GSTM1A. Belongs to the GST superfamily. Mu family. The Singapore human mutation and polymorphism database