What is the pH of Deoxyribonucleic Acid (DNA)?
There is no single answer, nor is there one for the more appropriate question, which is what is the pK of DNA. Remember that DNA is composed of four different bases: Adenosine, Thymidine, Cytosine and Guanidine. Each base has ionzable groups with different pKs. Combined with the pKs for the phosphate backbone, there are several titratable groups on DNA, and the pKs will depened on the quantity of A:T and G:C (which varies from individual to individual: viva la difference!). pH is a measure of the hydrogen ion in solution and can vary. Consider that water has a pK of 7.0, but the pH of water varies depending on the concentration of hydrogen ion. That’s why water can have a pH of 6.8 or 7.5 or whatnot. So you really should ask, what is the pK of DNA. The answer is: it depends on the base composition.
