Monoclonal antibodies prepared against the DNA polymerase from Thermus aquaticus are potent inhibitors of enzyme activity.

Recent interest in the unique properties of the DNA polymerase from Thermus aquaticus (TaqPol) has stemmed from its use in many laboratories for the polymerase chain reaction. We have produced a panel of nine distinct monoclonal antibodies to a recombinant form of TaqPol that have the following properties: (1) each binds TaqPol with high affinity (Kd < 10 nM); (2) eight of the nine arbitrarily selected monoclonal antibodies inhibit TaqPol activity completely; (3) the weak inhibitor is specific for TaqPol only while all eight strong inhibitors cross-react with the DNA polymerase from at least one other Thermus species as detected by either competitive ELISA, Western blotting, inhibition of enzyme activity or determination of binding by surface plasmon resonance; (4) these antibodies can be distinguished from each other by heavy chain class, cross-reactivity patterns, isoelectric points, and epitope mapping; and (5) these antibodies define seven non-overlapping epitopes. In addition, we show data from a preliminary experiment that demonstrates that at least one of these antibodies inhibits TaqPol by preventing DNA binding.