Zhang Yuntao, Iwamoto Takeo, Radke Gary, Kariya Yutaka, Suzuki Kiyoshi, Conrad Abigail H, Tomich John M, Conrad Gary W
Division of Biology, Kansas State University, Ackert Hall, Manhattan, Kansas 66506-4901, USA.
J Mass Spectrom. 2008 Jun;43(6):765-72. doi: 10.1002/jms.1373.
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.
在本研究中，描述了一种用于硫酸角质素（KS）寡糖靶板衍生化的快速且新颖的方法，以便随后通过基质辅助激光解吸电离（MALDI）质谱进行分析。标记的KS寡糖的MALDI -（飞行时间）-TOF光谱显示，通过芘丁酸酰肼（PBH）衍生化可实现显著改善的电离，并且每个光谱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 =硫酸盐的数量（n = 1、2、3……）。标记的KS寡糖的高能碰撞诱导解离（heCID）光谱显示出与激光诱导解离（LID）分析中观察到的类似化合物片段，这表明heCID和LID碎片化均可用于分析KS寡糖。此外，通过MALDI - TOF/TOF - MS对所有标记的KS寡糖进行了碎片化分析。在LID模式下，钠加合物显示出糖苷键的碎片化，主要产生Y/B/C离子，以及各种跨环裂解，为硫酸基团沿KS寡糖链的位置提供了准确信息。这种一步式靶板衍生化方法使MALDI - TOF/TOF - MS对KS的鉴定对于痕量生物样品而言快速、简单且高通量。
