DHFR, also known as Dihydrofolate reductase, is an enzyme that reduces dihydrofolic acid to tetrahydrofolic acid, using NADPH as electron donor, which can be converted to the kinds of tetrahydrofolate cofactors used in 1-carbon transfer chemistry. Dihydrofolate reductase deficiency has been linked to megaloblastic anemia. Recombinant Dihydrofolate reductase protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques