PH-DEPENDENCE OF ION-EXCHANGE EQUILIBRIUM OF PROTEINS

The adsorption equilibrium of bovine serum albumin on Q-sepharose, a s trong anion exchanger, was studied with batch equilibrium experiments at pH between 4 and 9 and ionic strengths between 5 and 440 mmol/L. De pendence of the adsorption equilibrium on the ionic strength was model ed as an ion exchange reaction. A simplified mechanism of this ion exc hange reaction also yielded an expression for the dependence of the eq uilibrium on the charge of the protein. This model describes the measu rements well, using fitted constants with physically realistic values.