Thermostable Polymerases

In 1976, Chien and colleagues first isolated Taq Polymerase from Thermus aquaticus, a thermophilic bacterium found in a hot spring in Yellowstone National Park. This polymerase was found to synthesize DNA at an optimal temperature of 75-80 °C and can survive temperatures up to 97 °C. Interestingly, while the authors were mainly interested in how life proliferates at extreme temperatures, they did not overlook the possibility of harnessing the enzyme for molecular biology. Sure enough, after Mullis invented the polymerase chain reaction in 1983, Taq was soon implemented as the active polymerizing enzyme by Saiki and others in 1988 giving birth to modern molecular biology. As if to follow Taq’s example, other thermostable polymerases eventually became prominent. Pfu Polymerase and Pfx Polymerase found uses in DNA amplifications requiring higher fidelity or accuracy. Tth polymerase with its intrinsic reverse transcriptase activity became ideal for reverse transcription and RT-PCR.