Taq DNA Polymerase

Taq DNA polymerase is a thermostable DNA polymerase which allows for the automation of the polymerase chain reaction (PCR) while simultaneously increasing both its speed and its accuracy over previous preparations.

Polymerase Chain Reaction (PCR) is a critically important technology in modern molecular biology, allowing for the amplification of an initially small quantity of target DNA in a relatively short period of time. PCR has a vast range of uses in molecular technology, including but not limited to disease diagnoses, forensic sciences, and DNA sequencing. The process makes use of a DNA polymerase and a series of denaturation and replication steps to amplify target DNA. By using a heat resistant DNA polymerase such as that derived from the thermophile T. aquaticus, the procedure may be automated as the polymerase will persist through the denaturation steps, removing the previous need to continuously refresh the DNA polymerase population and thereby greatly expanding the utility of this procedure.

T. aquaticus DNA polymerase (Taq DNA polymerase) is active at a broad range of high temperatures with peak activity near 75°C, allowing for it to remain active even when undergoing to harsh 95°C cycles necessary to denature dsDNA during a PCR reaction. Taq polymerase lacks 3' exonuclease proofreading activity, meaning that it is able to replicate DNA very rapidly. This lack of proofreading activity does make the Taq polymerase somewhat prone to errors in replication, with estimated error frequencies ranging from 2 x10-4 to 1×10-5, however these frequencies are low enough that they do not have a significant impact on biochemical analyses. Results from the use of Taq polymerase are comparable to or superior than DNA polymerases which were used before the advent of this heat-stable polymerase, such as the Klenow fragment of DNA Polymerase I from E. coli.

Owing to its advantages in automating the PCR process while simultaneously maintaining the integrity of copied DNA sequences, Taq DNA polymerase represents a critically important enzyme in even fairly basic laboratory procedures. As such, its purification is a beneficial tool to laboratories which frequently use this enzyme, and can be completed for a significantly lower price than buying commercial preparations.

Biology


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