Alumina-phosphate complexes for immobilization of biomolecules

Organic compounds containing the -PO3H2 function are strongly and specifically adsorbed by aluminum oxide in water within a large range of pH. The reversible character of the interaction allows the adsorbed organic phosphates to be displaced by inorganic phosphate buffers resulting in their purification by an affinity-like chromatographic procedure. The interaction between alumina and selected multifunctional compounds containing a phosphonate group yields a chemically activated alumina-phosphate complex onto which enzymes or other molecules can be immobilized. A number of proteases immobilized on alumina through such phosphate interactions proved to be active in the presence of organic solvents. As a consequence, enzyme-catalyzed peptide synthesis in a water-limited environment and optical resolution of amino acids in water-organic solvent emulsions can be accomplished.