Influence of charge state and sodium cationization on the electron detachment dissociation and infrared multiphoton dissociation of glycosaminoglycan oligosaccharides
Influence of charge state and sodium cationization on the electron detachment dissociation and infrared multiphoton dissociation of glycosaminoglycan oligosaccharides
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DOI：
10.1016/j.jasms.2008.03.010
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发表时间：
2008-06-01
影响因子：
3.2
通讯作者：
Amster, I. Jonathan
中科院分区：
文献类型：
--
作者：
Wolff, Jeremy J.;Laremore, Tatiana N.;Amster, I. Jonathan
电子脱离解离 (EDD) 傅里叶变换质谱最近被证明是硫酸化糖胺聚糖串联质谱分析的有用方法； （GAG）。 EDD 产生丰富的糖苷和交叉环片段，可用于定位 GAG 寡糖中的硫酸化位点。虽然 EDD 碎片可用于在单个串联质谱实验中表征 GAG，但 SO3 损失伴随着许多峰，并使所得质谱变得复杂。在这项工作中，我们证明了通过选择适当的 GAG 前体离子的电离态可以显着减少 SO3 损失。当电离度大于寡糖中硫酸基的数量时，在 EDD 质谱中观察到 SO 损失显着减少。这些数据表明，当电子从羧酸盐基团而不是硫酸盐基团分离时，SO3 损失就会减少。由于热力学原因，电子脱离优先发生在羧酸盐而不是硫酸盐上，前提是羧酸盐处于电离状态。羧酸根的电离是通过选择适当的前体离子电荷状态或通过用钠阳离子取代质子来实现的。通过添加钠阳离子来增加电离态会减少但不能消除相同 GAG 前体离子的红外多光子解离造成的 SO 损失。
Electron detachment dissociation (EDD) Fourier transform mass spectrometry has recently been shown to be a useful method for tandem mass spectrometry analysis of sulfated glycosaminoglycans; (GAGs). EDD produces abundant glycosidic and cross-ring fragmentations that are useful for localizing sites of sulfation in GAG oligosaccharides. Although EDD fragmentation can be used to characterize GAGs in a single tandem mass spectrometry experiment, SO3 loss accompanies many peaks and complicates the resulting mass spectra. In this work we demonstrate the ability to significantly decrease SO3 loss by selection of the proper ionized state of GAG precursor ions. When the degree of ionization is greater than the number of sulfate groups in an oligosaccharide, a significant reduction in SO, loss is observed in the EDD mass spectra. These data suggested that SO3 loss is reduced when an electron is detached from carboxylate groups instead of sulfate. Electron detachment occurs preferentially from carboxylate versus sulfate for thermodynamic reasons, provided that carboxylate is in its ionized state. Ionization of the carboxylate group is achieved by selecting the appropriate precursor ion charge state, or by the replacement of protons with sodium cations. Increasing the ionization state by sodium cation addition decreases, but does not eliminate, SO, loss from infrared multiphoton dissociation of the same GAG precursor ions.