Dynamic analysis of the binding process of bovine serum albumin on glutaraldehyde-activated controlled pore glass

Bovine serum albumin (BSA) was repeatedly injected into a column packed with aminopropyl-controlled pore glass activated with glutaraldehyde (GA-CPG). The experimental elution profile of BSA from the column was monitored with a UV detector and analyzed by a model, based on the assumption that two modes are involved in the binding of BSA onto GA-CPG. Binding process parameters such as bound amounts and binding rate constants were estimated by the curve-fitting method. The increase of ionic strength of the carrier solution reduced the total amount of BSA bound, suggesting an involvement of ionic interaction in the binding. The maximum bound amount was recognized at pH 6 with a carrier of lowionic strength, and at pH 7 for a higher ionic strength carrier. While reduction of GA-CPG with sodium borohydride remarkably decreased the bound amount, blocking treatment with amine did not lower the amount. This may mean that a functional group on the support, other than an aldehyde, is responsible for the binding of BSA. The bound amount of BSA at the restricted diffusion sites was noted to increase with rise in pH during the activation step with glutaraldehyde, whereas there was no significant difference in the total bound amount. This implies that aldol condensation of glutaraldehyde at alkaline pH could result in changes of the internal structure of the support.