Chai W, Luo J, Lim C K, Lawson A M
MRC Glycosciences Laboratory, Imperial College School of Medicine, Northwick Park Hospital, Harrow, Middlesex, U.K.
Anal Chem. 1998 May 15;70(10):2060-6. doi: 10.1021/ac9712761.
Among glycosaminoglycans, polysulfated heparin chains provide the greatest challenge to characterization due to high polarity, structural diversity, and sulfate lability. The present report demonstrates how electrospray mass spectrometry (ESMS) can be used to derive compositional information from pure and mixed fractions of heparin tetra- to decasaccharide fragments prepared by controlled digestion of heparin with heparinase I. It also describes an improved procedure for fractionation of heparin oligosaccharides up to octadecasaccharides. Ammonium salts prove to be superior to sodium salts, particularly for analysis of mixed components. In the mass spectrum of a hexasaccharide fraction, the identification of six major mass peaks that represent the known hexasaccharide structures confirms that ESMS analysis of heparin oligosaccharide fragments gives a close representation of their constituent composition. In addition to the previously identified components, several unreported oligosaccharides were detected in the spectra of octa- and decasaccharide fractions. The ESMS identification of the three major species in a decasaccharide fraction was confirmed after HPLC subfractionation and reanalysis. ESMS detection sensitivity of low picomole amounts of oligosaccharides can be readily achieved.
在糖胺聚糖中，多硫酸化肝素链因其高极性、结构多样性和硫酸酯不稳定性，在表征方面带来了最大挑战。本报告展示了如何使用电喷雾质谱法（ESMS）从通过用肝素酶I对肝素进行受控消化制备的肝素四糖至十糖片段的纯品和混合组分中获取组成信息。它还描述了一种改进的方法，用于分离高达十八糖的肝素寡糖。铵盐被证明优于钠盐，特别是对于混合组分的分析。在六糖组分的质谱图中，代表已知六糖结构的六个主要质量峰的鉴定证实，肝素寡糖片段的ESMS分析能很好地反映其组成成分。除了先前鉴定的组分外，在八糖和十糖组分的光谱中还检测到了几种未报道的寡糖。在高效液相色谱（HPLC）亚分级分离和重新分析后，证实了ESMS对十糖组分中三种主要成分的鉴定。可以很容易地实现低皮摩尔量寡糖的ESMS检测灵敏度。
