TaqPolymerase

Taq polymerase, also known as Taq DNA polymerase, is a thermostable DNA polymerase derived from the bacterium Thermus aquaticus. It catalyzes DNA synthesis in the 5' to 3' direction and is used to amplify DNA by the polymerase chain reaction (PCR). Its main advantage is stability at high temperatures, allowing repeated denaturation steps during PCR without enzyme loss.

Origin and discovery: Thermus aquaticus is a thermophilic bacterium found in hot springs. In the late 1980s, researchers isolated a DNA polymerase that remains active after exposure to high heat. The enzyme was described in the 1988 Saiki et al. paper, enabling rapid, automated PCR.

Properties: Taq polymerase has optimum activity around 72°C for extension and is robust across a range of temperatures. It lacks 3' to 5' exonuclease proofreading activity, which results in higher error rates compared with proofreading polymerases; this makes Taq suitable for routine amplification rather than high-fidelity applications.

Applications: It is the standard enzyme used in most PCR protocols, supporting cloning, sequencing, diagnostics, and research, by enabling exponential amplification of target DNA from small samples.

Variants and improvements: Commercial formulations offer hot-start options and optimized buffers. For applications requiring higher fidelity, alternative or engineered enzymes with proofreading activity are used, or Taq is paired with such polymerases in specialized kits.