Involved in ascorbate homeostasis. Maintains redox pools of ascorbate by recycling dihydroascorbate (DHA) to ascorbate. Involved in scavenging reactive oxygen species (ROS) under oxidative stresses. glutathione + RX = a halide anion + an S-substituted glutathione + H(+) 2 glutathione + L-dehydroascorbate = glutathione disulfide + L-ascorbate Monomer. Down-regulated during senescence. Belongs to the GST superfamily. DHAR family.