Conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles. Highly active towards 1-chloro-2,4-dinitrobenzene and organic isothiocyanates, but shows no detectable activity towards 1,2-dichloro-4-nitrobenzene, p-nitrobenzylchloride, trans-4-phenyl-3-buten-2-one (tPBO) and ethacrynic acid. May be associated with cellular proliferation. glutathione + RX = a halide anion + an S-substituted glutathione + H(+) Homodimer. The 83 N-terminal amino acids function as un uncleaved transit peptide, and arginine residues within it are crucial for mitochondrial localization. Expressed only in embryos. Not expressed in liver, lung, heart, kidney and ovary. Detected in embryos at stages 11-15, but not detected in unfertilized eggs. Belongs to the GST superfamily. Pi family.