Role of electrostatic forces in hydroxy and keto bile salt-albumin interactions: some experimental observations.

Proton binding to bovine serum albumin and effects on hydroxy and keto bile salts-albumin binding were studied within a pH range between 5 and 10. Electrostatic forces contribute to the binding of these ligands to albumin; prototropic groups of albumin such as imidazol are involved in the interaction. Bile salts binding produces a shift in pK of these groups. It is postulated that hydroxy bile salt-albumin binding is linked with the N in equilibrium with B transition of the protein, while for keto bile salts a microarrangement in the protein binding sites is driving the interaction.