Martin Cristina, Iberer Gunter, Ubiera Antonio, Carta Giorgio
Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904-4741, USA.
J Chromatogr A. 2005 Jun 24;1079(1-2):105-15. doi: 10.1016/j.chroma.2005.03.007.
This work provides a theoretical analysis of multicomponent adsorption kinetics for conditions typical of protein adsorption in porous ion exchangers as well as experimental results for the adsorption of lysozyme/cytochrome c mixtures in the cation exchanger SP-Sepharose-FF. The theory predicts the formation of overshoots in the intraparticle concentration profiles and in the total amount adsorbed for the more weakly adsorbed component. An analytical solution valid for the case where the isotherms are rectangular is developed and found to be in good agreement with the limiting behavior of the general numerical solution of the model equations. The experimental results show that the two proteins are competitively adsorbed and that an overshoot of adsorbed cytochrome c occurs during simultaneous adsorption. Model predictions based on the assumption that the adsorption isotherms are rectangular and that lysozyme completely displaces cytochrome c are in qualitative and quantitative agreement with the experimental kinetics suggesting that the overshoot phenomena observed with multicomponent systems in these resins can be explained with a diffusion model without the need to account for flux coupling or electrophoretic contributions to transport.
这项工作对多孔离子交换剂中蛋白质吸附典型条件下的多组分吸附动力学进行了理论分析，并给出了溶菌酶/细胞色素c混合物在阳离子交换剂SP-Sepharose-FF上吸附的实验结果。该理论预测了颗粒内浓度分布以及吸附较弱组分的总吸附量中会出现过冲现象。针对等温线为矩形的情况，推导出了一个解析解，发现它与模型方程一般数值解的极限行为吻合良好。实验结果表明，两种蛋白质存在竞争性吸附，且在同时吸附过程中会出现吸附的细胞色素c过冲现象。基于吸附等温线为矩形且溶菌酶完全取代细胞色素c这一假设的模型预测，在定性和定量上都与实验动力学相符，这表明在这些树脂中多组分体系中观察到的过冲现象可以用扩散模型来解释，而无需考虑通量耦合或电泳对传输的贡献。
