Dear colleagues: I was wondering if you could kindly share your thoughts and help me understand the relationship between pKa and affinity of a protein for a ligand. Are these two properties related? Specifically, does a lysine with a pKa of 8.5 have a greater affinity for a negatively charged ligand than a lysine with a pKa of 10.5 for the same ligand at physiological pH?
Any comments would be highly appreciated. Deepak