Bioaffinity Separations Using Reversed Micellar Extraction

It is shown that significant enhancements in the efficiency of protein recovery using reversed micelle extractants are possible if an affinity ligand surfactant is incorporated in the micellar phase formulation. The partitioning of the model protein concanavalin‐A was found to increase dramatically on addition of small amounts of octyl β‐D‐glucopyranoside (2 to 10 percent of the total surfactant concentration) to the organic reversed micellar phase, while transfer of ribonuclease‐A was essentially unaffected by the addition of this biological detergent. Glucose inhibited the solubilization of concanavalin‐A owing to competition for the binding sites between glucose and the affinity ligand. The experimental results were well described in terms of a simple thermodynamic model for the affinity partitioning of the protein between the two phases. Estimated binding constants for the protein‐ligand complex in the reversed micellar phase are consistent with published aqueous‐phase results.