关键词: 离子交换, 二乙氨乙基葡聚糖, 反离子, 吸附, 动力学, 线性梯度洗脱

Abstract: In the previous studies, a series of novel anion-exchangers, DEAE-dextran grafted Sepharose FF resins, were obtained, which exhibited high levels of both protein capacity and uptake rate. In this work, two typical DEAE-dextran grafted resins, FF-D50-DexD100 (mixed-ligand resin)and FF-DexD100 (grafting-ligand resin), were selected to investigate the effects of counterions on protein adsorption equilibria, uptake rate, dynamic binding and linear gradient eltion, with sodium salts of SCN^-, Cl^-, HPO₄^2- and SO₄^2-, and compared with the commercial resins, Q Sepharose FF, Q Sepharose XL and DEAE Sepharose FF, using bovine serum albumin (BSA) as the model protein. It was found that the four counterions showed different prefernces on the two DEAE-dextran modified resins, but the couterion preference orders of two DEAE-dextran modified resins were the same, which indicated that the ligand distribution (surface-ligand or grafting-ligand) did not affect the couterion preference. Furthermore, the counterions with weaker prefernces could accelerate the masstransfer of protein by promoting the "chain delivery" effect, and finally enchance the dynamic binding capacity of DEAE-dextran modified resins. Therefore, HPO₄^2- and SCN^- are suitable counterions for column binding and eltuion operation with DEAE-dextran grafted Sepharose FF resins, respecitively. The experimental result is expected to help optimizing anion exchange chromatograhpy process with DEAE-dextran modified resins.

Key words: ion exchange, DEAE-dextran grafting, counterions, adsorption, uptake kinetics, linear gradient elution