Purity >95% by SDS-PAGE. Glutathione S-transferase theta 1(GSTT1) is one of the GSTs' four main classes: alpha, mu, pi, theta. This enzyme is involved in activation and detoxification reactions and catalyzes the conjugation of industrial chemicals, e.g. epoxybutane, ethylene oxides, halomethane with glutathione. The absence of the GSTTI enzyme, might determine the individual risk for development of acquired aplastic anemia and acute myeloid leukemia. Recombinant human GSTT1, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.