Stellwagen Nancy C
Department of Biochemistry, University of Iowa , 51 Newton Road, Iowa City, Iowa 52242, United States.
J Phys Chem B. 2017 Mar 9;121(9):2015-2026. doi: 10.1021/acs.jpcb.6b10599. Epub 2017 Feb 24.
Free solution electrophoretic mobilities of polyelectrolytes with different charge densities have been analyzed using data taken from the literature. The polyions include single- and double-stranded DNA oligomers, small aromatic molecules, peptides, proteins, and synthetic copolymers. Mobility variations due to differences in the background electrolytes were minimized by calculating mobility ratios, dividing the mobility of each charge variant in each data set by the mobility of the most highly charged polyion in that data set. In all cases, the mobility ratios increase linearly with the logarithm of the fractional charge, not the first power of the charge as usually assumed. In addition, the mobility ratios observed for all polyelectrolytes, except for the synthetic copolymers, exhibit a common dependence on the logarithm of fractional charge. The unique results observed for the synthetic copolymers may be due to the flexibility of their hydrocarbon backbones, in contrast to the relatively rigid hydrophilic backbones of the other polyelectrolytes. The mobilities observed for the DNA charge variants are well predicted by the Manning electrophoresis equation, whereas the mobilities predicted by zeta potential theories are higher. However, mobility ratios calculated from both theories agree with the observed results.
利用从文献中获取的数据，对具有不同电荷密度的聚电解质的自由溶液电泳迁移率进行了分析。这些聚离子包括单链和双链DNA寡聚物、小的芳香族分子、肽、蛋白质和合成共聚物。通过计算迁移率比，将每个数据集中每个电荷变体的迁移率除以该数据集中电荷最高的聚离子的迁移率，从而使背景电解质差异导致的迁移率变化最小化。在所有情况下，迁移率比随分数电荷的对数呈线性增加，而不是像通常假设的那样随电荷的一次幂增加。此外，除了合成共聚物外，所有聚电解质的迁移率比都表现出对分数电荷对数的共同依赖性。合成共聚物观察到的独特结果可能是由于其碳氢主链的柔韧性，这与其他聚电解质相对刚性的亲水性主链形成对比。DNA电荷变体观察到的迁移率可以通过曼宁电泳方程得到很好的预测，而zeta电位理论预测的迁移率更高。然而，从这两种理论计算得到的迁移率比与观察结果一致。
