DNA Polymerase is purified from E. coli expressing a cloned DNA polymerase from Thermus aquaticus. The enzyme consists of a single polypeptide with a molecular weight of approximately 94 kDa. DNA Polymerase has 5′-3′ DNA polymerase activity and 5′-3′ exonuclease activity. Amplification of genomic DNA fragment up to 4 kb.