DESIGN OF SURFACTANTS SUITABLE FOR PROTEIN EXTRACTION BY REVERSED MICELLES

New surfactants have been synthesized for potential use in reversed mi cellar protein extraction operations. Preferential solubility of the s urfactant in an aliphatic solvent such as hexane, heptane, or isooctan e a nd the formation of reversed micelles accompanied with solubilizat ion of significant quantities of water can be achieved by using strong ly hydrophobic, twin alkyl chains as the hydrophobic moiety. Different surfactants having identical water-solubilizing capacities can have s ignificantly different behavior in protein extractions, where extracti on efficiency appears to be governed by the nature of the interfacial complex that forms between surfactants and proteins. Bulky surfactant chains provide a steric hindrance to the adsorption of the surfactant to the protein surface, thus inhibiting solvation of the protein/surfa ctant complex, and hence protein extraction. Under these conditions, a precipitate forms either in the bulk aqueous phase or at the interfac e. Surfactants that can form a close-packed complex with the protein a re excellent protein-solubilizing agents. Dioleyl phosphoric acid (DOL PA) appears to be the best surfactant currently available for protein extraction. (C) 1997 John Wiley & Sons, Inc.