Taq DNA Polymerase

Taq DNA Polymerase is a highly thermostable recombinant DNA polymerase derived from the thermophile; Thermus aquaticus.  A recombinant protein expressed in E. coli that carries the pol gene for Thermus aquaticus. The molecular weight of the recombinant protein is 94kD.  The Taq polymerase is able to amplify DNA up to 5kb with an elongation velocity of 0.9-1.2kb/min at 70-75°C. The error rate of this Taq polymerase is ~2.2x10-5 nucleotide-1 cycle-1. Taq DNA polymerase catalyzes the 5’-3’ synthesis of DNA. The enzyme has no detectable 3’-5’ proofreading exonuclease activity; and possesses low 5’-3’ exonuclease activity; which results in a 3’-dA overhang on the PCR product.

One unit (U) of Taq polymerase is defined as the amount of enzyme needed to catalyze the incorporation of 10nm of deoxyribonucleotides into acid-insoluble material in 30 minutes at 70°C using herring sperm DNA as a substrate.