Taq DNA Polymerase is purified from E. coli. expressing a Thermus aquaticus DNA polymerase gene. This enzyme has a 5′ → 3′ DNA polymerase and a 5′ → 3′ exonuclease activity but lacks a 3′ → 5′ exonuclease activity. The enzyme consists of a single polypeptide with a molecular weight of approximately 94 kDa. Taq DNA polymerase is heat-stable and will synthesize DNA at elevated temperatures from single-stranded templates in the presence of a primer. Taq Polymerase is recommended for use in routine PCR reactions. The buffer system is optimized for high specificity and guarantees minimal by-product formation. We supplied Taq Polymerase with appropriate buffers. Usually 1-1.5 u of Taq DNA Polymerase are used in 50 µl of reaction mix. Higher Taq DNA Polymerase concentrations may cause synthesis of nonspecific products. However, if inhibitors are present in the reaction mix (e.g., if the template DNA used is not highly purified), higher amounts of Taq DNA Polymerase (2-3 u) may be necessary to obtain a better yield of amplification products.