Separation of Membrane Proteins Solubilized with a Nondenaturing Detergent and a High Salt Concentration by Hydroxyapatite High-Performance Liquid Chromatography

Abstract Ceramic hydroxyapatite high-performance liquid chromatography with a solvent containing high concentrations of salts was used for the separation of membrane proteins solubilized under nondenaturing and high salt conditions. The chromatographic conditions were optimized using sodium cholate as the detergent. By this method, most membrane proteins, prepared from rat liver rough microsomes, were effectively resolved from each other with a protein recovery of more than 90%. The method also allowed the single-step purification of the ribosome-binding protein, p34, from a microsomal membrane protein fraction. The good resolution with this method should be applicable to the isolation and characterization of a variety of membrane proteins on the analytical and semipreparative scales. With only the substitution of sodium cholate with other nondenaturing detergents, this method may also be applicable to the purification of membrane proteins requiring such nondenaturing detergents with retention of their biological activities.