Leiden University Medical Center, Biomolecular Mass Spectrometry Unit, Department of Parasitology, Leiden, The Netherlands.
Mass Spectrom Rev. 2011 Jul-Aug;30(4):664-80. doi: 10.1002/mas.20337. Epub 2011 May 10.
Mass spectrometric rearrangement reactions have been reported for a large variety of compounds such as peptides, lipids, and carbohydrates. In the case of carbohydrates this phenomenon has been described as internal residue loss. Resulting fragment ions may be misinterpreted as fragments arising from conventional glycosidic bond cleavages, which may result in incorrect structural assignment. Therefore, awareness of the occurrence of glycan rearrangements is important for avoiding misinterpretation of tandem mass spectra. In this review mass spectrometric rearrangements of both derivatized and underivatized (native) oligosaccharide structures are discussed. Similar phenomena have been reported for glycopeptides, labeled glycan structures and other biomolecules containing a carbohydrate part. Rearrangements in oligosaccharides and glycoconjugates have been observed with different types of mass spectrometers. Most of the observed carbohydrate rearrangement reactions appear to be linked to the presence of a proton. Hence, tandem mass spectrometric analysis of alkali adducts or deprotonated ions often prevents rearrangement reactions, while they may happen with high efficacy with protonated glycoconjugates.
质谱重排反应已经在各种化合物中得到了报道，如肽、脂类和碳水化合物。在碳水化合物的情况下，这种现象被描述为内部残基损失。由此产生的碎片离子可能会被误解为来自常规糖苷键裂解的片段，这可能导致结构分配的错误。因此，意识到聚糖重排的发生对于避免串联质谱的错误解释是很重要的。在这篇综述中，讨论了衍生化和未衍生化（天然）寡糖结构的质谱重排。类似的现象也已经在糖肽、标记的聚糖结构和其他含有碳水化合物部分的生物分子中报道过。在不同类型的质谱仪中都观察到了寡糖和糖缀合物的重排。大多数观察到的碳水化合物重排反应似乎与质子的存在有关。因此，碱加合物或去质子化离子的串联质谱分析通常可以防止重排反应，而与质子化糖缀合物一起，这些反应可能会以很高的效率发生。
