Conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles. Shows high activity towards 4-nitrobenzyl chloride (4-NBC). Also has lower activity towards 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP), cumene hydroperoxide, 1-chloro-2,4-dinitrobenzene (CDNB), 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl), and ethacrynic acid. glutathione + RX = a halide anion + an S-substituted glutathione + H(+) Homodimer. Expressed strongly in liver, and at lower levels in kidney and testis. Belongs to the GST superfamily. Theta family.