Platinum™ Tfi Exo(-) DNA Polymerase is recombinant Tfi Exo(-) DNA Polymerase complexed with a proprietary antibody mix that inhibits polymerase activity at ambient temperature, allowing room-temperature reaction setup. Activity is restored after the initial denaturation step in PCR cycling at 94°C, providing an automatic 'hot start' for increased specificity, sensitivity, and yield. Tfi Exo(-) DNA Polymerase is purified from E. coli. expressing cloned mutants of the Thermus filiformis DNA polymerase gene. This enzyme has 5'→3' polymerase activity, but lacks both 5'→3' and 3'→5' exonuclease activity for improved yield and robustness. Tfi Exo(-) DNA polymerase is heat-stable and will synthesize DNA at elevated temperatures from single-stranded templates in the presence of a primer.

Applications
Platinum™ Tfi Exo(-) DNA Polymerase can be used in protocols that currently use Platinum™ Taq DNA Polymerase without modification. PCR performance is comparable to that of Platinum™ Taq in yield, specificity, fidelity, and robustness. Like Platinum™ Taq, Platinum™ Tfi Exo(-) DNA Polymerase has a nontemplate-dependent terminal transferase activity that adds a single deoxyadenosine (A) to the 3' ends of PCR products.