Polyol-promoted adsorption of serum proteins to amphiphilic agarose-based adsorbents

We tested the promotion of protein adsorption onto amphiphilic agarose-based adsorbents by addition of high concentrations of polyols during the adsorption phase. C3- to C5-polyols were inefficient in promoting protein adsorption, whereas some of the C6-polyols studied (sorbitol, dulcitol and mannitol) could promote serum protein adsorption onto mercaptomethylene pyridine-derivatized agarose, octyl- and phenyl-Sepharose. Sorbitol was the most potent protein adsorption promoter, with a direct relation between the amount of protein adsorbed and the concentration of sorbitol. For each chromatographic gel, the effects of increasing concentrations of sorbitol or sodium sulfate on protein adsorption were similar and two-dimensional electrophoresis revealed the preservation of the protein adsorption specificity whether sorbitol or sodium sulfate was used. These results show that a water-structuring salt or a polyol can promote protein adsorption in the same manner, presumably by a related mechanism.