Weiskopf A S, Vouros P, Harvey D J
Department of Chemistry, Northeastern University, Boston, Massachusetts 02115, USA.
Anal Chem. 1998 Oct 15;70(20):4441-7. doi: 10.1021/ac980289r.
Electrospray ionization-ion trap mass spectrometry, with its capacity to perform multiple stages of fragmentation (MSn), is demonstrated as an effective method for the structural characterization of permethylated N-linked complex glycoprotein oligosaccharides. Complex glycan structural features, such as N-acetyllactosamine antenane, neuraminic acids, and nonreducing terminal GlcNAc monosaccharides, commonly suppress cross-ring and core saccharide cleavages in traditional MS/MS experiments. Using ion trap mass spectrometry, removal of these substituents permits determination of branching patterns and intersaccharide linkages by MS3 and MS4. Both sequence and linkage data are obtained for N-acetyllactosamine and sialyl-N-acetyllactosamine oligosaccharide antennae from biantennary glycans using MS3, and the location of a bisecting GlcNAc residue is also established after exposing the core pentasaccharide. Higher-order experiments further illustrate the potential of electrospray ionization-quadrupole ion trap mass spectrometry for carbohydrate analysis, as MS8 is used to produce significant and otherwise unobtainable branching information for an oligosaccharide from chicken ovalbumin. These studies constitute further evidence of the unique role that ion trap mass spectrometry can assume in the area of oligosaccharide analysis.
电喷雾电离-离子阱质谱法具有进行多阶段碎裂（MSn）的能力，已被证明是对全甲基化N-连接复合糖蛋白寡糖进行结构表征的有效方法。复杂聚糖的结构特征，如N-乙酰乳糖胺天线、神经氨酸和非还原末端GlcNAc单糖，在传统的MS/MS实验中通常会抑制跨环和核心糖的裂解。使用离子阱质谱法，去除这些取代基后可通过MS3和MS4确定分支模式和糖间连接。利用MS3可获得来自双天线聚糖的N-乙酰乳糖胺和唾液酸-N-乙酰乳糖胺寡糖天线的序列和连接数据，在暴露核心五糖后还可确定平分型GlcNAc残基的位置。高阶实验进一步说明了电喷雾电离-四极杆离子阱质谱法在碳水化合物分析中的潜力，因为MS8用于从鸡卵清蛋白的寡糖中产生重要的、否则无法获得的分支信息。这些研究进一步证明了离子阱质谱法在寡糖分析领域可发挥的独特作用。
