Abstract:

Ion exchange chromatography (IEC)is a common and powerful technique for the purification of proteins. The ligand density and pore size of the resins have significant effects on the separation behaviors of protein. In the present work, three kinds of crossed-linked agarose gel with different agarose concentrations were used as the matrices to represent various pore sizes, and anionic ligand, diethylaminothyl (DEAE), was coupled with different ligand densities. The preparation conditions, including the reaction temperature, time, DEAE concentration and NaOH concentration, were optimized to control the ionic exchange capacity. A series of DEAE resins with different ligand densities and pore sizes were obtained. The adsorption isotherms and kinetics of bovine serum albumin (BSA) were measured on these resins. The saturated adsorption capacity increased with the increasing of ligand densities and the decreasing of pore sizes at the range tested. For the adsorption kinetics, the pore size influenced significantly the effective pore diffusivities. The results demonstrated that both the pore size and ligand density affect the static and dynamic adsorption. The pore size dominates the diffusion and mass transfer of protein, while the ligand density affects the interactions between ligand and protein.