Entropic trapping binding mechanism: its likely role in receptor-ligand and other biochemical systems

Entropy-driven binding continues to be discovered in receptor-ligand systems as well as in other important biochemical systems. In receptor-ligand systems the "thermodynamic agonist-antagonist discrimination" is often found: in some such receptor types the binding of antagonists is entropy-driven, in others this is a characteristic of the agonist binding. The interpretation of the entropy-driven binding mechanism in the systems in question is still rather elusive. Experimental findings clearly indicate that the entropic binding mechanisms which are usually considered cannot provide a consistent interpretation in these cases. Entropic trapping was therefore proposed in our earlier papers as a possible binding model which does not contradict the experimental facts. It is pointed out here that through the work which has appeared subsequently the existence of such a mechanism has been firmly established and that its role is strongly corroborated by the more recent data from several biochemical systems.