Choosing the right DNA polymerase for your PCR

Success of the polymerase chain reaction (PCR) largely depends on the choice of the appropriate DNA polymerase. DNA polymerase is one of the major components needed for setting up a PCR. For PCR, a thermo-stable DNA polymerase is essential, so that it can endure higher temperatures during the cycling conditions. Therefore, thermo-stable DNA polymerases serve as a key player in the current methods of DNA amplification and sequencing.

Based on their amino acid sequences, DNA polymerases are categorized into six families: A, B, C, D, X and Y. Thermophilic enzymes are found in all the six families. Same reaction is catalyzed by all DNA polymerases, that is, adding nucleotides to the 3'-end of the DNA primer to synthesize the new DNA strand complementary to the template DNA. The thermo-stable DNA polymerases synthesize DNA in a template-directed manner, and require primer-template hybrid to begin the synthesis.

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