Pulyaeva H, Wheeler D, Garner M M, Chrambach A
Section on Macromolecular Analysis, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-0001.
Electrophoresis. 1992 Sep-Oct;13(9-10):608-14. doi: 10.1002/elps.11501301123.
Electrophoresis of lambda phage DNA was carried out in solutions at various concentrations of uncrosslinked polyacrylamide of 0.6, 1, 5 and 9 x 10(6) molecular weight (Mw) with narrow Mw distribution. By inspection of mobilities in the various concentration ranges, it appears that mobilities decrease, and retardation increases, with increasing Mw. The relation between electrophoretic retardation and the Mw of the polymer was also interpreted (i) in the manner previously applied to nonlinear Ferguson plots and compatible with the Ogston model; and (ii) empirically, on the basis of the first derivatives of the functions describing the Ferguson plots at the polymer concentrations used. Interpretation (i) shows that the retardation increases linearly in the order of 0.6, 1, 5 and 9 x 10(6) Mw of polyacrylamide. Interpretation (ii) shows a nonlinear increase of retardation in the Mw range 5 to 9 x 10(6), and a decrease in retardation as Mw is raised from 0.6 to 5.0 x 10(6). Hypothetically, interpretation (ii) can be explained mechanistically by a progressive change, as the polymer size is increased, from a collision with the surface of the polymer fiber to one occurring after permeation in the interior of a random-coiled fiber. Interpretation (i) may fail to detect that change due to the large difference between DNA mobility in solutions of the smallest polymer and the free mobility. DNA peak detection in all of the four size classes of polyacrylamide in solution is limited to relatively narrow ranges of polymer concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
在分子量（Mw）分别为0.6、1、5和9×10⁶且Mw分布狭窄的未交联聚丙烯酰胺的各种浓度溶液中，对λ噬菌体DNA进行了电泳。通过检查不同浓度范围内的迁移率，似乎随着Mw的增加，迁移率降低，阻滞作用增强。电泳阻滞与聚合物Mw之间的关系也通过以下两种方式进行了解释：（i）以前应用于非线性弗格森图且与奥格斯顿模型相符的方式；（ii）基于在所使用的聚合物浓度下描述弗格森图的函数的一阶导数进行经验解释。解释（i）表明，聚丙烯酰胺Mw为0.6、1、5和9×10⁶时，阻滞作用呈线性增加。解释（ii）表明，在5至9×10⁶的Mw范围内，阻滞作用呈非线性增加，而当Mw从0.6提高到5.0×10⁶时，阻滞作用降低。假设地，解释（ii）可以从机理上解释为，随着聚合物尺寸的增加，从与聚合物纤维表面的碰撞逐渐变为在无规卷曲纤维内部渗透后发生的碰撞。解释（i）可能由于最小聚合物溶液中DNA迁移率与自由迁移率之间的巨大差异而未能检测到这种变化。在溶液中所有四种尺寸类别的聚丙烯酰胺中检测DNA峰都限于相对较窄的聚合物浓度范围。
