title: Oligosaccharides from human milk as revealed by matrix-assisted laser desorption/ionization mass spectrometry.
abstract: In this study neutral and acidic oligosaccharide fractions prepared from human milk have been investigated using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The fraction of neutral oligosaccharides was separated by gel permeation chromatography (GPC) and the resulting subfractions were analyzed by MALDI-MS using the positive ion mode. Several low-molecular-weight glycans (degree of polymerization up to 13) were observed whose structures have already been elucidated. In addition, a variety of so far unknown large-sized carbohydrates was detected whose molecular weights range from M(r) 2242 to 8000. The large-sized glycans which possess a low abundance appear to be composed of both lactosamine and fucose residues attached to the lactose unit at the reducing end of the sugar chains with a highly variable stochiometry. Following subfractionation by GPC, acidic (i.e., containing sialic acid) glycans were analyzed by MALDI-MS using both positive and negative ion mode. Because of the inferior stability of acidic glycans, various matrices were applied and compared with respect to signal intensity, resolution, and analyte stability.
authors.affiliation: Institute for Medical Physics and Biophysics, University of Muenster, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Stahl
authors.forename: S
authors.initials: S
authors.lastname: Thurl
authors.forename: J
authors.initials: J
authors.lastname: Zeng
authors.forename: M
authors.initials: M
authors.lastname: Karas
authors.forename: F
authors.initials: F
authors.lastname: Hillenkamp
authors.forename: M
authors.initials: M
authors.lastname: Steup
authors.forename: G
authors.initials: G
authors.lastname: Sawatzki
mesh_terms: D002850:Chromatography, Gel; D004355:Drug Stability; D005260:Female; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods* / Q000706:statistics & numerical data; D008895:Milk, Human / Q000737:chemistry*; D015394:Molecular Structure; D008970:Molecular Weight; D009844:Oligosaccharides / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D011134:Polysaccharides / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D012794:Sialic Acids / Q000032:analysis
chemical_list: D009844:Oligosaccharides; D011134:Polysaccharides; D012794:Sialic Acids