Psurek Arndt, Feuerstein Sophie, Willbold Dieter, Scriba Gerhard K E
School of Pharmacy, Department of Pharmaceutical Chemistry, University of Jena, Jena, Germany.
Electrophoresis. 2006 May;27(9):1768-75. doi: 10.1002/elps.200500673.
The CE separation of alpha-helical polypeptides composed of 14-31 amino acid residues has been investigated using aqueous and nonaqueous BGEs. The running buffers were optimized with respect to pH. Generally, higher separation selectivities were observed in nonaqueous electrolytes. This may be explained by a change in the secondary structure when changing from water to organic solvents. Circular dichroism spectra revealed a significant increase in helical structures in methanol-based buffers compared to aqueous buffers. This change in secondary structure of the polypeptides contributed primarily to the different separation selectivity observed in aqueous CE and NACE. For small oligopeptides of two to five amino acid residues no significant effect of the solvent was observed in some cases while in other cases a reversal of the migration order occurred when changing from aqueous to nonaqueous buffers. As these peptides cannot adopt secondary structures the effect may be attributed to a shift of the pKa values in organic solvents compared to water.
使用水性和非水性背景电解质（BGEs）研究了由14 - 31个氨基酸残基组成的α - 螺旋多肽的毛细管电泳（CE）分离。运行缓冲液针对pH进行了优化。一般来说，在非水性电解质中观察到更高的分离选择性。这可能是由于从水转变为有机溶剂时二级结构发生了变化。圆二色光谱显示，与水性缓冲液相比，基于甲醇的缓冲液中螺旋结构显著增加。多肽二级结构的这种变化主要导致了在水性毛细管电泳和非水毛细管电泳中观察到的不同分离选择性。对于由两到五个氨基酸残基组成的小寡肽，在某些情况下未观察到溶剂的显著影响，而在其他情况下，从水性缓冲液转变为非水性缓冲液时迁移顺序发生了反转。由于这些肽不能形成二级结构，这种影响可能归因于与水相比，有机溶剂中pKa值的变化。
