Zinc–human serum albumin association: testimony of two binding sites

The zinc cation (Zn2+) binding to human serum albumin (HSA) was studied using a non-equilibrium approach in order to prove two HSA binding sites. The effect of the bulk solvent pH and column temperature T on this binding and the corresponding thermodynamic data were also investigated. It appeared that the association process can be divided into two pH value ranges due to a predominant Zn2+ interaction with either HSA site I or site II. It was also demonstrated that the Zn2+ affinity for the site II was weakly affected by modifying the mobile phase pH whereas for the site I, the affinity constant increased strongly with increasing the pH of the bulk solvent.