gor, also known as Glutathione reductase, belongs to the class-I pyridine nucleotide disulfide oxidoreductase family. The main function of the protein is to maintain high levels of reduced glutathione in the cytosol. With the concomitant oxidation of NADPH, Glutathione reductase transforms oxidized glutathione to the reduced form. The active site of the protein is a redox-active disulfide bond. Recombinant E. coli gor protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.