title: Sequence analysis of alginate-derived oligosaccharides by negative-ion electrospray tandem mass spectrometry.
abstract: 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).
authors.affiliation: Institute of Marine Drug and Food, Ocean University of China, 26603, Shandory, China.
authors.forename: Zhenqing
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Institute of Marine Drug and Food, Ocean University of China, 26603, Shandory, China. glyu@ouc.edu.cn.
authors.forename: Guangli
authors.initials: G
authors.lastname: Yu
authors.affiliation: Institute of Marine Drug and Food, Ocean University of China, 26603, Shandory, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Institute of Marine Drug and Food, Ocean University of China, 26603, Shandory, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Liu
authors.affiliation: Institute of Marine Drug and Food, Ocean University of China, 26603, Shandory, China.
authors.forename: Huashi
authors.initials: H
authors.lastname: Guan
authors.affiliation: MRC Glycosciences Laboratory, Faculty of Medicine, Imperial College London, Northwick Park and St. Mark's Campus, HA1 3UJ, Harrow, Middlesex, UK.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Lawson
authors.affiliation: MRC Glycosciences Laboratory, Faculty of Medicine, Imperial College London, Northwick Park and St. Mark's Campus, HA1 3UJ, Harrow, Middlesex, UK. w.chai@imperial.ac.uk.
authors.forename: Wengang
authors.initials: W
authors.lastname: Chai
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002240:Carbohydrate Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D017421:Sequence Analysis / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000464:Alginates; D009844:Oligosaccharides