Howard P. Isermann Department of Chemical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA.
Biotechnol Bioeng. 1997 Oct 20;56(2):119-29. doi: 10.1002/(SICI)1097-0290(19971020)56:2<119::AID-BIT1>3.0.CO;2-S.
In contrast to high molecular weight polyelectrolyte displacers, the efficacy of low molecular weight displacers are dependent on both mobile phase salt and displacer concentration. This sensitivity to the operating conditions opens up the possibility of carrying out selective displacement where the product(s) of interest can be selectively displaced while the low affinity impurities can be desorbed in the induced salt gradient ahead of the displacement train, and the high affinity impurities either retained or desorbed in the displacer zone. This type of displacement combines the operational advantages of step gradient and the high resolution inherent in a true displacement process, in a single operation. Theoretical expressions are presented for establishing selective displacement operating conditions (initial salt concentration, displacer concentration) based on the Steric Mass Action parameters of the displacer and the linear Steric Mass Action parameters of the feed proteins. Experimental results are presented to elucidate the concept of selective displacement in both cation and anion exchange systems. A mixture of alpha-lactalbumin and beta-lactoglobulin A and B has been used for anion-exchange systems; a four-protein mixture consisting of ribonuclease B, bovine and horse heart cytochrome c, and lysozyme has been employed in cation exchange systems. This article also demonstrates that on-line monitoring can be readily employed for the selective displacement process, thus facilitating the scale-up and control of the process. This work sets the stage for the development of robust large scale high resolution separations using selective displacement chromatography. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 119-129, 1997.
与高分子量聚电解质置换剂相反，低分子量置换剂的效果取决于流动相盐和置换剂浓度。这种对操作条件的敏感性为选择性置换开辟了可能性，其中感兴趣的产物可以被选择性地置换，而低亲和力杂质可以在置换列车前的诱导盐梯度中解吸，而高亲和力杂质可以保留或在置换区中解吸。这种置换类型将步梯度的操作优势与真正置换过程固有的高分辨率结合在单次操作中。提出了理论表达式，用于根据置换剂的空间位阻质量作用参数和进料蛋白质的线性空间位阻质量作用参数来建立选择性置换操作条件（初始盐浓度、置换剂浓度）。实验结果阐明了在阳离子交换和阴离子交换系统中选择性置换的概念。使用α-乳白蛋白和β-乳球蛋白 A 和 B 的混合物用于阴离子交换系统；在阳离子交换系统中使用了由核糖核酸酶 B、牛和马心细胞色素 c 和溶菌酶组成的四蛋白混合物。本文还表明，在线监测可以很容易地用于选择性置换过程，从而促进该过程的放大和控制。这项工作为使用选择性置换色谱法开发稳健的大规模高分辨率分离奠定了基础。（c）1997 年 John Wiley & Sons，Inc. 《生物技术与生物工程》56:119-129,1997.
