DuSP21 (Dual specificity protein phosphatase 21) belongs to the protein-tyrosine phosphatase family. Dual specificity protein phosphatases (DuSPs) inactivate their target kinases by dephosphorylating both the phosphoserine/threonine and phosphotyrosine residues. This enzyme can dephosphorylate single and diphosphorylated synthetic MAPK peptides, with preference for the phosphotyrosine and diphosphorylated forms over phosphothreonine. It is exclusively expressed in testis where is preferentially dephosphorylates phosphotyrosine residues in MAPK peptides. Recombinant human DuSP21 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques. MW: 24.1 kDa (214 aa, 1-190 aa + His T