Effect of the pore sizes of nylon affinity membranes on γ-globulin adsorption

L-Phenylalanine was immobilized on nylon membranes with two pore diameters (0.45 mum and 1 mum), by activation with 1,4-butanediol diglycidyl ether, and the effect of pore size on the affinity adsorption of gamma -globulin studied by batch and kinetic methods. Experiment shows that adsorption on both affinity membranes obeys the Freundlich model. The accessible pore volume for adsorption of proteins on the membrane with 0.45 mum diameter pores is less than for that with 1 mum diameter pores. The adsorption capacity of affinity membranes with 1 mum diameter pores is 2.5-fold that of membranes with 0.45 mum diameter pores. Feed-rate has a larger effect on affinity adsorption on the membrane with 0.45 mum diameter pores than on that with 1 mum diameter pores. Small pores on the affinity membrane do not cause broadening of the elution peak. It is concluded that affinity interaction and separation occur mainly in the large pores, and small pore size does not favor improvement of adsorption capacity, gamma -Globulin 85.1% pure can be obtained in one step from human plasma by use of the affinity membrane with 0.45 mum diameter pores.