Menon M K, Zydney A L
Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716, USA.
Biotechnol Bioeng. 1999 May 5;63(3):298-307.
Electrostatic interactions can have a significant impact on protein transmission through semipermeable membranes. Experimental data for the transport of bovine serum albumin (BSA) through a polyethersulfone ultrafiltration membrane were obtained in different salt solutions over a range of pH and salt concentrations. Net BSA charge under the same conditions was evaluated from mobility data measured by capillary electrophoresis. The results show that specific ionic composition, in addition to solution pH and ionic strength, can strongly affect the rate of protein transport through semipermeable ultrafiltration membranes. The effects of different ions on BSA sieving are due primarily to differences in ion binding to the protein, which leads to significant differences in the net protein charge at a given pH and ionic strength. This effect could be described in terms of an effective protein radius, which accounts for the electrostatic exclusion of the charged protein from the membrane pores. These results provide important insights into the nature of the electrostatic interactions in membrane systems.
静电相互作用对蛋白质通过半透膜的传输可能产生重大影响。在不同的盐溶液中，于一系列pH值和盐浓度条件下，获取了牛血清白蛋白（BSA）通过聚醚砜超滤膜传输的实验数据。通过毛细管电泳测量的迁移率数据评估了相同条件下BSA的净电荷。结果表明，除了溶液pH值和离子强度外，特定的离子组成会强烈影响蛋白质通过半透超滤膜的传输速率。不同离子对BSA筛分的影响主要归因于离子与蛋白质结合的差异，这导致在给定pH值和离子强度下蛋白质净电荷存在显著差异。这种效应可以用有效蛋白质半径来描述，该半径考虑了带电蛋白质从膜孔的静电排斥。这些结果为膜系统中静电相互作用的本质提供了重要见解。
