Taq DNA Polymerase is a specialised thermostable enzyme isolated from the thermophilic bacterium Thermus aquaticus. The recombinant form of this enzyme is expressed in E. coli. It is highly processive, recombinant polymerase which catalyses the addition of mononucleotide units to the 3’-OH end of a primer chain. It remains functional even after prolonged incubation at 95 °C. This enzyme possesses 5’-3’ exonuclease activiy.

Taq DNA Polymerase is used for the DNA polymerase chain reaction (PCR) in order to amplify DNA sequences. Other applications include RT-PCR, DNA sequencing and DNA labeling.