Hydrophobic charge induction chromatography: salt independent protein adsorption and facile elution with aqueous buffers

A new form of protein chromatography, hydrophobic charge induction, is described. Matrices prepared by attachment of weak acid and base ligands were uncharged at adsorption pH. At low ligand densities, protein adsorption was typically promoted with lyotropic salts. At higher ligand densities, chymosin, chymotrypsinogen and lysozyme were adsorbed independently of ionic strength. A pH change released the electrostatic potential of the matrix and weakened hydrophobic interactions, inducing elution. Matrix hydrophobicity and titration range could be matched to protein requirements by ligand choice and density. Both adsorption and elution could be carried out within the pH 5–9 range.