AAT Bioquest

What is the optimal magnesium concentration for Taq polymerase?

Posted February 17, 2023


The optimal magnesium concentration for Taq polymerase is between 1 and 5 mM in standard PCR reactions. For buffer preparation, the most commonly used concentration OF MgCl2 is 2 Mm. 

Magnesium chloride (MgCl2) is essential for the optimization of a PCR protocol. It increases DNA amplification by acting as a cofactor and boosting the enzymatic activity of DNA polymerase. It also facilitates the primer binding at specific sites during PCR reaction. 

Using the correct magnesium concentration is important to create appropriate PCR conditions for the proper amplification of the desired fragments of DNA templates. Too much magnesium can cause an increase in nonspecific binding of primers, resulting in errors in DNA replication. In some cases, it may also lead to primer dimer formation. Too little results in weak amplification and reduced yield or complete PCR failure as primers fail to base pair with the DNA template.  

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