Conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles (By similarity) (PubMed:10903867). Participates in the formation of novel hepoxilin regioisomers (By similarity). glutathione + RX = a halide anion + an S-substituted glutathione + H(+) Homodimer. Belongs to the GST superfamily. Mu family.