Wolff Jeremy J, Laremore Tatiana N, Leach Ii Franklin E, Linhardt Robert J, Amster I Jonathan
Departme nt of Chemistry, University of Georgia, Athens, GA 30602, USA.
Eur J Mass Spectrom (Chichester). 2009;15(2):275-81. doi: 10.1255/ejms.951.
The structural analysis of sulfated carbohydrates such as glycosaminoglycans (GAGs) has been a long- standing challenge for the field of mass spectrometry. The dissociation of sulfated carbohydrates by collisionally- activated dissociation (CAD) or infrared multiphoton dissociation (IRMPD), which activate ions via vibrational excitation, typically result in few cleavages and abundant SO(3) loss for highly sulfated GAGs such as heparin and heparan sulfate, hampering efforts to determine sites of modification. The recent application of electron activation techniques, specifically electron capture dissociation (ECD) and electron detachment dissociation (EDD), provides a marked improvement for the mass spectrometry characterization of GAGs. In this work, we compare ECD, EDD and IRMPD for the dissociation of the highly sulfated carbohydrate sucrose octasulfate (SOS). Both positive and negative multiply-charged ions are investigated. ECD, EDD and IRMPD of SOS produce abundant and reproducible fragmentation. The product ions produced by ECD are quite different than those produced by IRMPD of SOS positive ions, suggesting different dissociation mechanisms as a result of electronic versus vibrational excitation. The product ions produced by EDD and IRMPD of SOS negative ions also differ from each other. Evidence for SO(3) rearrangement exists in the negative ion IRMPD data, complicating the assignment of product ions.
对硫酸化碳水化合物（如糖胺聚糖，GAGs）进行结构分析，长期以来一直是质谱领域的一项挑战。通过碰撞激活解离（CAD）或红外多光子解离（IRMPD）对硫酸化碳水化合物进行解离，这些方法通过振动激发来激活离子，对于高度硫酸化的GAGs（如肝素和硫酸乙酰肝素），通常会导致很少的裂解和大量的SO(3)损失，从而阻碍了确定修饰位点的工作。电子激活技术的最新应用，特别是电子捕获解离（ECD）和电子脱附解离（EDD），为GAGs的质谱表征提供了显著的改进。在这项工作中，我们比较了ECD、EDD和IRMPD对高度硫酸化碳水化合物八硫酸蔗糖（SOS）的解离情况。对正负多电荷离子都进行了研究。SOS的ECD、EDD和IRMPD产生了丰富且可重复的碎片。ECD产生的产物离子与SOS正离子的IRMPD产生的产物离子有很大不同，这表明由于电子激发与振动激发导致了解离机制的不同。SOS负离子的EDD和IRMPD产生的产物离子也彼此不同。负离子IRMPD数据中存在SO(3)重排的证据，这使得产物离子的归属变得复杂。
