Protein-Ligand Association Equilibria

A common function of all proteins bestowed with biological activity is the non-covalent binding of specific or non-specific ligands. The association of substrates or diverse effector molecules – inhibitors or activators – to an enzyme, and the association of biologically active molecules to a membrane receptor or to a soluble transporter, are just some of the more familiar examples. The binding of protons, H+, to a protein is another particular case of protein-ligand interaction.