Mechref Yehia, Novotny Milos V
Department of Chemistry, National Center for Glycomics and Glycoproteomics, METACyt Biochemical Analysis Center, Indiana University, Bloomington, IN 47405, USA.
Mass Spectrom Rev. 2009 Mar-Apr;28(2):207-22. doi: 10.1002/mas.20196.
The occurrence of multiple glycosylation sites on a protein, together with the number of glycan structures which could potentially be associated with each site (microheterogeneity) often leads to a large number of structural combinations. These structural variations increase with the molecular size of a protein, thus contributing to the complexity of glycosylation patterns. Resolving such fine structural differences has been instrumentally difficult. The degree of glycoprotein microheterogeneity has been analytically challenging in the identification of unique glycan structures that can be crucial to a distinct biological function. Despite the wealth of information provided by the most powerful mass spectrometric (MS) and tandem MS techniques, they are not able to readily identify isomeric structures. Although various separation methods provide alternatives for the analysis of glycan pools containing isomeric structures, capillary electrophoresis (CE) is often the method of choice for resolving closely related glycan structures because of its unmatched separation efficiency. It is thus natural to consider combining CE with the MS-based technologies. This review describes the utility of different CE approaches in the structural characterization of glycoproteins, and discusses the feasibility of their interface to mass spectrometry.
蛋白质上多个糖基化位点的出现，以及每个位点可能与之相关的聚糖结构数量（微观不均一性），常常导致大量的结构组合。这些结构变异随着蛋白质分子大小的增加而增多，从而导致糖基化模式的复杂性增加。解析如此细微的结构差异在很大程度上具有难度。在鉴定对于独特生物学功能可能至关重要的独特聚糖结构方面，糖蛋白微观不均一性的程度在分析上具有挑战性。尽管最强大的质谱（MS）和串联质谱技术提供了丰富的信息，但它们无法轻易鉴定异构体结构。尽管各种分离方法为分析含有异构体结构的聚糖库提供了替代方案，但由于其无与伦比的分离效率，毛细管电泳（CE）通常是解析密切相关聚糖结构的首选方法。因此，将CE与基于MS的技术相结合是很自然的。本综述描述了不同CE方法在糖蛋白结构表征中的应用，并讨论了它们与质谱联用的可行性。
