A DNA Polymerase is a vital biological enzyme that is present in DNA replication. In the process, DNA copies into two daughter DNA molecules and synthesizes a new DNA strand from the existing strand by adding dNTPs to the growing DNA.
The DNA Polymerase has two crucial roles in replication: 5’ to 3’ exonuclease polymerase activity and 3’ to 5’ exonuclease proofreading activity. As the polymerase binds to DNA, it adds nucleotide in the direction of 5’ to 3’.
Unfortunately, because it disables at a higher temperature, DNA Polymerase is not suitable for a type of replication called Polymerase Chain Reaction (PCR). Taq DNA Polymerase, on the other hand, plays an essential role in PCR.
What is Taq Polymerase?
Taq DNA Polymerase is a highly thermostable recombinant DNA polymerase. It is named after Thermus aquaticus, the heat-tolerant bacterium from which it isolates itself. The molecular weight of the Taq Polymerase is 94kD, and it amplifies DNA up to 5kb with an elongation velocity of 0.9-1.2kb/min at 70-75°C.
What is Polymerase Chain Reaction (PCR)?
Polymerase Chain Reaction, or PCR, is a replication technique that produces numerous copies of a specific DNA region in vitro (in a test tube rather than an organism). PCR is utilized in various areas of biology and medicine, including molecular biology research, medical diagnostics, and ecology.
PCR relies upon Taq Polymerase, a thermostable DNA polymerase. It also requires DNA primers that are designed specifically for the DNA region of interest, as well as template DNA and nucleotides (DNA building blocks).
In a PCR reaction, you will assemble the key ingredients in a tube, along with cofactors the enzyme requires. The ingredients undergo repeated cycles of heating and cooling that ultimately synthesize DNA.
There are also three basic steps you must follow to achieve PCR, including:
- Denaturation (96 °C): Heat the reaction strongly to separate, or denature, the DNA strands.
- Annealing (55-65 °C): Cool the reaction so the primers can bind to their complementary sequences on the single-stranded template DNA.
- Extension (72 °C): Raise the reaction temperatures so Taq polymerase extends the primers, synthesizing new strands of DNA.
The cycle repeats itself 25-35 times in a typical PCR reaction, which generally takes 2-4 hours, depending on the length of the DNA region being copied. If the reaction is efficient, the target region can go from just one or a few copies to billions.
The Role of Taq Polymerase in PCR
Due to its key role in synthesizing and amplifying new strands of DNA, Taq DNA Polymerase is essential to Polymerase Chain Reaction (PCR).
Like other DNA polymerases, Taq Polymerase can only produce DNA if it has a primer, a short sequence of 20 nucleotides that provide a starting point for DNA synthesis. However, it is also a thermostable DNA polymerase that can work at higher temperatures.
Taq DNA Polymerase is highly efficient, so it becomes fully functional as it reaches its optimum temperature. It also has a half-life of more than two hours (at a temperature of 92 °C), a high-amplification capacity, and the ability to add 150 nucleotides per second.
Choose G-Biosciences for Your PCR Essentials
At G-Biosciences, we offer a variety of kits and products for your PCR and Taq DNA Polymerase applications. To place your order, visit our website today.
