Affinity adsorption of recombinant human interferon-α on monosize dye-affinity beads

Monosize, nonporous poly(glycidyl methacrylate) [poly(GMA)] beads were prepared by dispersion polymerization. Cibacron Blue F3GA was covalently attached onto the poly(GMA) beads for adsorption of recombinant interferon-alpha (rHuIFN-alpha). Monosize poly(GMA) beads were characterized by scanning electron microscopy. Dye-carrying beads (1.73 mmol/g) were used in the adsorption-elution studies. The effect of initial concentration of rHuIFN-alpha, pH, ionic strength, and temperature on the adsorption efficiency was studied in a batch system. Nonspecific adsorption of rHuIFN-a on the beads was 0.78 mg/g. Dye attachment Significantly increased the rHuIFN-alpha adsorption up to 181.7 mg/g. Equilibrium adsorption of rHuIFN-alpha onto the dye-carrying beads increased with increasing temperature. Negative change in free energy (Delta G(0) < 0) indicated that the adsorption was a thermodynamically favorable process. Delta S and Delta H values were 146.1 J/mol K and -37.39 kJ/mol, respectively. Significant amount of the adsorbed rHuIFN-alpha (up to 97.2%) was eluted in the elution medium containing 1.0M NaCl in I h. To determine the effects of adsorption conditions on possible conformational changes of rHuIFN-alpha structure, fluorescence spectrophotometry was employed. We concluded that dye-affinity beads can be applied for rHuIFN-a adsorption without causing any significant conformational changes. Repeated adsorption-elution processes showed that these beads are suitable for rHuIFN-alpha adsorption. (c) 2006 Wiley Periodicals, Inc.