In addition to 5'-3' DNA polymerase activity, it also possesses 3'-5' exonuclease (proofreading) activity. Pfu DNA Polymerase exhibits the lowest error rate of any thermostable DNA polymerase studied, and is even up to ten-fold more accurate than normal Taq DNA polymerase. Consequently, Pfu DNA Polymerase is useful for polymerization reactions requiring high-fidelity synthesis.