CHARGE-TRANSFER CHROMATOGRAPHY USED TO STUDY THE INTERACTION OF CHLORHEXIDINE WITH PROTEINS AND AMINO-ACIDS

The interaction of the antibacterial agent chlorhexidine amethylene-bi s-/5-(4-chlorophenyl)-bis-guanidine/) with human albumin and pepsin an d with amino acids was studied with reversed-phase charge transfer chr omatography in the presence of various monovalent cations. It was esta blished that the mobility of chlorhexidine increases in the presence o f ions in the lower concentration range (0.001 - 0.1 M) then increases at higher concentrations. The ion radii significantly influences the effect. Stepwise regression analysis proved that the chlorhexidine bin ds both to pepsin and human albumin, the binding is stronger with huma n albumin. The ions modify the character of chlorhexidine-human albumi n binding indicating the hydrophilic character of the interaction. Exc ept Asp and Glu the other amino acids exhibited weak interactions with chlorhexidine, no significant difference was found between the intera ctive strength of L- and D-forms of Asp and Glu. Our data make probabl e that hydrophilic binding of chlorhexidine to the acidic side chains in proteins may be involved in its mode of action.