Taqpolymerasen

Taq polymerase, or Taq DNA polymerase, is a thermostable DNA polymerase used to amplify DNA in the polymerase chain reaction (PCR). It is derived from Thermus aquaticus, a thermophilic bacterium found in hot springs. Its heat tolerance allows the enzyme to survive the high-temperature denaturation steps of PCR, enabling rapid DNA amplification in a single tube without enzyme replenishment. Since its introduction, Taq polymerase became a standard tool in molecular biology and clinical diagnostics.

Biochemical properties: The enzyme catalyzes DNA synthesis in the 5' to 3' direction and requires a template, primers, Mg2+ and dNTPs. It has an optimum activity around 72°C and remains active at elevated temperatures, with a relatively fast extension rate. A key limitation is the lack of 3' to 5' exonuclease proofreading activity, which contributes to comparatively higher error rates relative to proofreading DNA polymerases. Taq polymerase commonly leaves a single adenine nucleotide appended to the 3' ends of PCR products, a feature that can simplify cloning.

Variants and uses: Taq polymerase is widely sold in various formulations, including hot-start versions that reduce non-specific amplification and kits that combine it with other enzymes or buffers for specific applications. For experiments requiring higher fidelity, researchers may use alternative enzymes with proofreading activity or employ enzyme blends. The term Taq polymerases can refer to the family of Thermus aquaticus–derived thermostable polymerases used in PCR and related techniques.