Basak S K, Ladisch M R
Laboratory of Renewable Resources Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
Anal Biochem. 1995 Mar 20;226(1):51-8. doi: 10.1006/abio.1995.1190.
Electrophoretic mobilities, mu, of nine proteins (M(r) 14,200 to 70,000) in 28 mM Tris/47 mM glycine buffer at pH 8.77 and 5 mM ionic strength were measured by laser Doppler velocimetry and correlated to ratios of charge (q) to molecular weight (M(r)) and shape factor (f/f0) by the equation mu(f/f0) = (Aq/Mpr-B). This correlation was previously reported for peptides and proteins for mu measured at 100 mM ionic strength. When A = 6.048 x 10(-3), B = 1.13 x 10(-5), and p = 2/3, the correlation fitted 51 measured and literature values over the molecular weight range of 178 to 140,000 for components whose electrophoretic mobilities ranged from +13.35 x 10(-5) to -19.7 x 10(-5) cm2/(V.s). The experimental measurements confirm the general suitability of p = 2/3 and show that the familiar charge/mass relation for electrophoresis is applicable to proteins in low-ionic-strength buffers which are typical of electrochromatography systems. Extrapolation of the correlation to different ionic strengths indicates that a low-ionic-strength buffer amplifies differences of electrophoretic mobility as a function of charge/mass, while high ionic strength diminishes such differences.
在pH 8.77、离子强度为5 mM的28 mM Tris/47 mM甘氨酸缓冲液中，通过激光多普勒测速法测量了9种蛋白质（分子量为14,200至70,000）的电泳迁移率μ，并通过方程μ(f/f0) = (Aq/Mpr - B)将其与电荷（q）与分子量（M(r)）之比以及形状因子（f/f0）相关联。此前已有报道在100 mM离子强度下测量的肽和蛋白质的这种相关性。当A = 6.048×10⁻³、B = 1.13×10⁻⁵且p = 2/3时，该相关性适用于电泳迁移率范围为 +13.35×10⁻⁵至 -19.7×10⁻⁵ cm²/(V·s)的178至140,000分子量范围内的51个测量值和文献值。实验测量结果证实了p = 2/3的总体适用性，并表明电泳中常见的电荷/质量关系适用于电色谱系统典型的低离子强度缓冲液中的蛋白质。将该相关性外推到不同离子强度表明，低离子强度缓冲液会放大电泳迁移率随电荷/质量的差异，而高离子强度则会减小这种差异。
