Our full range of PCR products includes the 96 Well Amplification Plate, the 0.2 and 0.5 ml tubes for PCR and strips for solid-phase PCR.
DNA Polymerase
A “good” DNA polymerase is not a universal concept but depends on the specific application, requiring a balance of properties like thermostability, processivity (the rate of nucleotide addition), fidelity (accuracy of replication), and also how long it remains on the template. For standard PCR, Taq polymerase is a popular, thermostable choice derived from the bacterium Thermus aquaticus. For higher accuracy, a proofreading polymerase with 3′ to 5′ exonuclease activity, such as a Pfu variant, is preferred. In isothermal applications, heat-stable polymerases like the top enzyme from Bacillus stearothermophilus are used, and engineered variants provide enhanced features such as resistance to inhibitors or the ability to replicate modified DNA templates.
Key Traits of an Effective DNA Polymerase
The “goodness” of a DNA polymerase depends on the specific laboratory or industrial application, but certain characteristics are generally desirable.
Thermostability:
The enzyme must withstand the high temperatures of PCR without denaturing.
Processivity:
The polymerase needs to efficiently and rapidly add many nucleotides to the growing DNA strand, extending the primer across the template.
Fidelity:
For applications requiring accuracy, the polymerase should have a low error rate to minimize mutations during DNA amplification.
Exonuclease Activity:
Some polymerases possess 3′ to 5′ exonuclease activity, which allows them to “proofread” their work, correcting misincorporated nucleotides and increasing accuracy.
Strand Displacement:
Some polymerases can “unwind” the DNA helix, a useful trait for certain amplification methods.
Inhibitor Resistance:
The ability to tolerate common inhibitors found in challenging sample types is crucial for some applications.