Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences , Soochow University , Suzhou , Jiangsu 215021 , China.
Departments of Chemistry and Chemical Biology, Biology, Chemical and Biological Engineering, and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , 110 Eighth Street , Troy , New York 12180 , United States.
Anal Chem. 2019 Jan 2;91(1):846-853. doi: 10.1021/acs.analchem.8b03500. Epub 2018 Dec 17.
Glycosaminoglycans (GAGs) are biologically and pharmacologically important linear, anionic polysaccharides containing various repeating disaccharides sequences. The analysis of these polysaccharides generally relies on their chemical or enzymatic breakdown to disaccharide units that are separated, by chromatography or electrophoresis, and detected, by UV, fluorescence, or mass spectrometry (MS). Isoelectric focusing (IEF) is an important analytical technique with high resolving power for the separation of analytes exhibiting differences in isoelectric points. One format of IEF, the capillary isoelectric focusing (cIEF), is an attractive approach in that it can be coupled with mass spectrometry (cIEF-MS) to provide online focusing and detection of complex mixtures. In the past three decades, numerous studies have applied cIEF-MS methods to the analysis of protein and peptide mixtures by positive-ion mode mass spectrometry. However, polysaccharide chemists largely rely on negative-ion mode mass spectrometry for the analysis of highly sulfated GAGs. The current study reports a negative-ion mode cIEF-MS method using an electrokinetically pumped sheath liquid nanospray capillary electrophoresis-mass spectrometry (CE-MS) coupling technology. The feasibility of this negative-ion cIEF-MS method and its potential applications are demonstrated using chondroitin sulfate and heparan sulfate oligosaccharides mixtures.
糖胺聚糖（GAGs）是具有生物学和药理学重要性的线性阴离子多糖，含有各种重复的二糖序列。这些多糖的分析通常依赖于它们的化学或酶解，将其分解为二糖单元，然后通过色谱或电泳进行分离，并通过紫外光、荧光或质谱（MS）进行检测。等电聚焦（IEF）是一种具有高分辨率的重要分析技术，用于分离等电点不同的分析物。IEF 的一种形式，毛细管等电聚焦（cIEF），是一种很有吸引力的方法，因为它可以与质谱（cIEF-MS）结合，提供复杂混合物的在线聚焦和检测。在过去的三十年中，许多研究应用 cIEF-MS 方法通过正离子模式质谱分析蛋白质和肽混合物。然而，糖化学家长期以来依赖于负离子模式质谱来分析高度硫酸化的 GAGs。本研究报告了一种使用电动泵送鞘液纳米喷雾毛细管电泳-质谱（CE-MS）联用技术的负离子 cIEF-MS 方法。通过使用软骨素硫酸和肝素硫酸寡糖混合物证明了这种负离子 cIEF-MS 方法的可行性及其潜在应用。
