Catalyzes the conjugation of GSH to a wide variety of electrophilic alkylating agents. Also involved in the metabolism of lipid hydroperoxides, prostaglandins and leukotriene A4 and in binding of non-substrate hydrophobic ligands such as bile acids, a number of drugs and thyroid hormones. This GST does not exhibit peroxidase activity. glutathione + RX = a halide anion + an S-substituted glutathione + H(+) Homodimer or heterodimer (with a subunit from group CL-4). The variations were found from AA sequencing and imply there are multiple forms of CL-3. Belongs to the GST superfamily. Alpha family.