Thiophilic adsorption--a new method for protein fractionation.

Divinylsulphone-activated agarose to which mercaptoethanol is coupled showed very selective group adsorption of human serum proteins, in particular the immunoglobulins. The adsorption increases markedly in the presence of high concentrations of neutral water-structure forming salts and is distinct from adsorptions based on hydrophobic interaction. A characteristic feature of this new type of adsorbent is the structure of the groups attached to the polymer, P, i.e., R-S-CH2-CH2-SO2-CH2-CH2-O-P, where R is a small aliphatic residue. Our results indicate that the thioether sulphur and the adjacent sulphone group act cooperatively and are apparently necessary to maintain the distinct behaviour of such absorbents.