Two-component protein adsorption to the cation exchanger S Sepharose FF.

A model system, consisting of bovine serum albumin, lysozyme and the cation exchanger S Sepharose FF, was used to investigate multicomponent protein adsorption to ion exchangers. Two models, one based on a complete absence of competition between adsorbing molecules and the other a competitive model, based on the assumption that all adsorption sites are available to both proteins, have been compared to experimental results. Evidence for competitive adsorption was seen in experiments in which breakthrough curves and the profiles of adsorbed proteins in packed beds were determined. However, although the results for packed-bed experiments were more closely predicted by the fully competitive model, some discrepancies were found suggesting that when considering multicomponent protein adsorption to ion exchangers it may also be necessary to take account of factors such as the molecular size of the adsorbing proteins and any potential inter-protein interactions, factors which may hinder the development of a general model of multicomponent protein adsorption to ion exchangers.