In the present work, a rapid and novel method of on-target plate derivatization of keratan sulfate (KS) oligosaccharides for subsequent analysis by matrix-assisted laser desorption and ionization (MALDI) mass spectrometry is described. MALDI-(time-of-flight)-TOF spectra of labeled KS oligosaccharides revealed that significantly improved ionization can be accomplished through derivatization with pyrenebutyric acid hydrazide (PBH), and the most abundant peak in each spectrum corresponds to the singly charged molecular ion [M − H]− or [M + (n − 1)Na − nH]−, where n = the number of sulfates (n = 1, 2, 3…). The high-energy collision-induced dissociation (heCID) spectra of labeled KS oligosaccharides displayed fragments of compounds similar to those observed with laser-induced dissociation (LID) analysis, suggesting that both heCID and LID fragmentations can be used to analyze KS oligosaccharides. Moreover, fragmentation analysis of all labeled KS oligosaccharides was performed by MALDI-TOF/TOF-MS. With LID mode, sodium adducts showed fragmentation of glycosidic linkages with mainly Y/B/C ions, as well as various cross-ring cleavages providing exact information for the positions of sulfate groups along the KS oligosaccharide chains. This one-step on-target derivatization method makes MALDI-TOF/TOF-MS identification of KS fast, simple and highly throughput for trace amounts of biological samples. Copyright © 2008 John Wiley & Sons, Ltd.
在本研究中,描述了一种快速而新颖的靶向载体衍生化
角鲨烷硫酸盐(KS)
寡糖的方法,以便随后通过基质辅助激光解吸离子化(MALDI)质谱进行分析。标记的KS
寡糖的MALDI-(飞行时间)-TOF谱显示,通过与
芘丁酸肼(PBH)衍生化,能够显著提高电离效率,且每个谱图中最丰富的峰对应于单电荷分子离子 [M − H]− 或 [M + (n − 1)Na − nH]−,其中 n 表示
硫酸盐的数量(n = 1, 2, 3…)。标记KS
寡糖的高能碰撞诱导解离(heCID)谱显示了与激光诱导解离(LID)分析中观察到的化合物类似的片段,表明heCID和LID的解离都可以用于分析KS
寡糖。此外,还通过MALDI-TOF/TOF-MS对所有标记的KS
寡糖进行了片段分析。在LID模式下,
钠加合物表现出糖苷键的解离,主要为Y/B/C离子,以及各种交环断裂,为KS
寡糖链上
硫酸根位置提供了确切的信息。这种一步法靶向衍生化方法使得MALDI-TOF/TOF-MS对KS的鉴定变得快速、简单且能够高通量处理微量
生物样品。版权所有 © 2008 John Wiley & Sons, Ltd.