In the PCR technology the DNA segment is replicated over a billion times. This repeated replication is catalyzed by the enzyme.

Taq polymerase is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA.
T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is $75-80^{\circ }\mathrm{C}$, with a half-life of greater than 2 hours at $92.5^{\circ }\mathrm{C},40$ minutes at $95^{\circ }\mathrm{C}$ and 9 minutes at $97.5^{\circ }\mathrm{C}$, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at $72^{\circ }\mathrm{C}$.