Zhang Zhenqing, Yu Guangli, Zhao Xia, Liu Haiying, Guan Huashi, Lawson Alexander M, Chai Wengang
Institute of Marine Drug and Food, Ocean University of China, 26603, Shandory, China.
MRC Glycosciences Laboratory, Faculty of Medicine, Imperial College London, Northwick Park and St. Mark's Campus, HA1 3UJ, Harrow, Middlesex, UK.
J Am Soc Mass Spectrom. 2006 Apr;17(4):621-630. doi: 10.1016/j.jasms.2006.01.002. Epub 2006 Feb 28.
Negative-ion electrospray tandem mass spectrometry (ES-MS/MS) with collision-induced dissociation (CID) is attempted for sequence determination of alginate oligosaccharides, derived from polyanionic alginic acid, polymannuronate, and polyguluronate by partial depolymerization using either alginate lyase or mild acid hydrolysis. Sixteen homo- and hetero-oligomeric fragments were obtained after fractionation by gel-filtration and strong anion exchange high performance liquid chromatography. The product-ion spectra of these alginate oligosaccharides were dominated by intense B-, C-, Y-, and Z-type ions together with (0,2)A- and (2,5)A-ions of lower intensities. Internal mannuronate residues (M) produce weak but specific decarboxylated Z(int)-ions (Z(int) - 44 Da; int: denotes internal), which can be used for distinction of M and a guluronate residue (G) at an internal position. A reducing terminal M or G, although neither gives rise to a specific ion, can be identified by differences in the intensity ratio of fragment ions of the reducing terminal residue [(2,5)A(red)]/[(0,4)A(red)] (red: denotes reducing terminal).
尝试采用负离子电喷雾串联质谱法（ES-MS/MS）并结合碰撞诱导解离（CID）来测定藻酸盐寡糖的序列。这些藻酸盐寡糖由聚阴离子海藻酸、聚甘露糖醛酸和聚古洛糖醛酸通过使用海藻酸裂解酶或温和酸水解进行部分解聚而得到。通过凝胶过滤和强阴离子交换高效液相色谱分离后，获得了16个同聚和杂聚寡聚片段。这些藻酸盐寡糖的产物离子谱主要由强烈的B型、C型、Y型和Z型离子以及强度较低的(0,2)A-和(2,5)A-离子组成。内部的甘露糖醛酸残基（M）会产生微弱但特征性的脱羧Z(int)-离子（Z(int) - 44 Da；int表示内部），可用于区分内部位置的M和古洛糖醛酸残基（G）。还原性末端的M或G虽然都不会产生特定离子，但可通过还原性末端残基的碎片离子强度比[(2,5)A(red)]/[(0,4)A(red)]（red表示还原性末端）的差异来鉴定。
