TDP2 is a member of a superfamily of divalent cation-dependent phosphodiesterases. The protein associates with CD40, tumor necrosis factor (TNF) receptor-75 and TNF receptor associated factors (TRAFs), and inhibits nuclear factor-kappa-B activation. This protein has sequence and structural similarities with APE1 endonuclease, which is involved in both DNA repair and the activation of transcription factors. Recombinant human TDP2 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.