Conjugation of reduced glutathione to a wide number of exogenous and endogenous hydrophobic electrophiles. Acts on 1,2-epoxy-3-(4-nitrophenoxy)propane, phenethylisothiocyanate 4-nitrobenzyl chloride and 4-nitrophenethyl bromide. Displays glutathione peroxidase activity with cumene hydroperoxide. glutathione + RX = a halide anion + an S-substituted glutathione + H(+) Homodimer. Found in erythrocyte. Expressed at low levels in liver. In lung, expressed at low levels in Clara cells and ciliated cells at the alveolar/bronchiolar junction. Absent from epithelial cells of larger bronchioles. The GSTT1 gene is absent from 38% of the population. The presence or absence of the GSTT1 gene is coincident with the conjugator (GSST1+) and non-conjugator (GSTT1-) phenotypes respectively. The GSTT1+ phenotype can catalyze the glutathione conjugation of dichloromethane. Belongs to the GST superfamily. Theta family. The Singapore human mutation and polymorphism database