Exhibits glutathione-dependent thiol transferase activity (By similarity). Has dehydroascorbate reductase activity and may contribute to the recycling of ascorbic acid (By similarity). Participates in the biotransformation of inorganic arsenic and reduces monomethylarsonic acid (MMA) (By similarity). Protects against environmental stress and oxidative stress (PubMed:17901115). glutathione + RX = a halide anion + an S-substituted glutathione + H(+) 2 glutathione + L-dehydroascorbate = glutathione disulfide + L-ascorbate 2 glutathione + H(+) + methylarsonate = glutathione disulfide + H2O + methylarsonous acid Homodimer. Expressed in the intestinal cells. Expressed in late embryos, during the L1 to L4 stages of larval development and in adult hermaphrodites. RNAi-mediated knockdown results in increased sensitivity and reduced survival in response to oxidative stress inducers cumene hydroperoxide, jugalone, paraquat and arsenite, and to heat shock treatment. Belongs to the GST superfamily. Omega family.