ADSORPTION AND ELUTION OF BOVINE GAMMA-GLOBULIN USING AN AFFINITY MEMBRANE CONTAINING HYDROPHOBIC AMINO-ACIDS AS LIGANDS

A hollow-fibre affinity membrane containing hydrophobic amino acids as ligands was prepared by the radiation-induced grafting of glycidyl methacrylate onto a porous polyethylene hollow fibre and subsequent coupling with phenylalanine (Phe) or tryptophan (Trp). The densities of the Phe and Trp ligand of the resulting affinity membrane were 0.4 and 0.4 mol/kg, respectively. The Trp-containing affinity membrane exhibited a higher amount of adsorbed bovine gamma-globulin (BGG) than the Phe-containing membrane. To evaluate the adsorption behaviour of the membrane, the BGG-containing buffer solution was permeated from the inside to the outside of the Trp-containing hollow-fibre affinity membrane through the ligand-immobilized pores. The breakthrough curves as a function of effluent volume coincided irrespective of the flow-rate, i.e. the residence time (55 220 s) of the solution across the membrane (thickness 0.83 mm), as a result of negligible mass transfer resistance. A series of chromatographic procedures, (adsorption-washing-elution) was repeated twice and a satisfactory quantitative elution was attained. The reproducible profile of the flux and the protein concentration assured a quantitative cycle of chromatography using the affinity membrane containing Trp as a ligand.