It is important to have extra dNTPs and magnesium so the reaction does not run out of components.
dNTPS
- dNTPs, termed deoxynucleotide triphosphates, are the nucleotide bases added to the growing DNA strand by the DNA polymerase.
MgCl2
- Magnesium ion (Mg2+) functions as a cofactor for the activity of the DNA polymerase and is commonly delivered as a MgCl2 solution. The concentration of MgCl2 influences the stringency of the interaction between the primers and the template DNA.
Salt and Buffers
- Salt and buffers stabilize polymerase function and formation of primer-template hybrids. Buffers often contain Tris-HCl, KCl, and sometimes MgCl2.
