Rodthongkum Nadnudda, Washington Jacqueline D, Savariar Elamprakash N, Thayumanavan S, Vachet Richard W
Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Anal Chem. 2009 Jun 15;81(12):5046-53. doi: 10.1021/ac900661e.
Amphiphilic homopolymers that self-assemble into reverse micelles in nonpolar solvents have been used by us in the context of a two-phase liquid-liquid extraction protocol to selectively extract peptides from aqueous solution for MALDI-MS detection. In this manuscript, we investigate the scope of these materials in terms of its extraction capabilities, using compounds with varying isoelectric points (pI) and pK(a) values over a range of aqueous solution pHs. We find that the aqueous solution pH and analyte pK(a) values are the major factors controlling extraction selectivity. We also find that the experimental extraction efficiencies correspond very well with the fractional compositions of species calculated using analyte pK(a) values, indicating that these extraction materials can be used to simultaneously generate titration-type curves for each individual peptide in a mixture. We predict that such titration curves, along with accurate mass measurements, could represent a new way of improving protein identification procedures.
我们已经在两相液-液萃取方案的背景下使用了两亲性均聚物，它们在非极性溶剂中自组装成反胶束，用于从水溶液中选择性萃取肽以进行基质辅助激光解吸电离质谱（MALDI-MS）检测。在本论文中，我们研究了这些材料在萃取能力方面的适用范围，使用了在一系列水溶液pH值下具有不同等电点（pI）和pKa值的化合物。我们发现水溶液pH值和分析物的pKa值是控制萃取选择性的主要因素。我们还发现实验萃取效率与使用分析物pKa值计算的物种分数组成非常吻合，这表明这些萃取材料可用于同时为混合物中的每个单独肽生成滴定型曲线。我们预测，这样的滴定曲线以及精确的质量测量，可能代表一种改进蛋白质鉴定程序的新方法。
