Exhibits 3'-exonuclease and apurinic/apyrimidinic (AP) endonuclease activities (in vitro). Show preferential AP endonuclease activity on double-stranded DNA substrates and 3'- exonuclease activity on single-stranded DNA. . This is the function of TATDN3 (TatD DNase domain containing 3, ENSG00000203705).