title: Evidence of the presence of 2-O-beta-D-xylopyranosyl-alpha-l-arabinofuranose side chains in barley husk arabinoxylan.
abstract: (Glucurono)arabinoxylans were extracted from barley husks and degraded with endo-beta-xylanase or subjected to periodate oxidation. The released oligosaccharide fragments were separated and isolated on Biogel-P2, and their structures were determined by NMR spectroscopy. The oligosaccharides identified consisted of beta-d-(1-->4)-linked xylopyranosyl residues, of which some were substituted at O-3 with alpha-l-arabinofuranosyl groups or at O-2 with 4-O-methylglucuronic acid. In addition to these substituents, a disaccharide side chain, 2-O-beta-d-xylopyranosyl-alpha-l-arabinofuranose, attached at position O-3 of the main chain, was proved to exist in arabinoxylan from barley husks. The compound was fully characterized with NMR, and all (1)H and (13)C NMR signals were assigned. The arabinose to xylose ratio was low (approximately 0.2) and no 2,3-disubstitution existed. No blocks of substituted xylose residues could be observed along the main chain.
authors.affiliation: Chalmers University of Technology, Department of Chemical and Biological Engineering, Biopolymer Technology, SE-412 96 Göteborg, Sweden. paul.gatenholm@chem.chalmers.se
authors.forename: Anders
authors.initials: A
authors.lastname: Höije
authors.forename: Corine
authors.initials: C
authors.lastname: Sandström
authors.forename: Johannes P
authors.initials: JP
authors.lastname: Roubroeks
authors.forename: Roger
authors.initials: R
authors.lastname: Andersson
authors.forename: Suresh
authors.initials: S
authors.lastname: Gohil
authors.forename: Paul
authors.initials: P
authors.lastname: Gatenholm
mesh_terms: D002240:Carbohydrate Sequence; D001467:Hordeum / Q000737:chemistry*; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D025942:Oligosaccharides, Branched-Chain / Q000737:chemistry; D010504:Periodic Acid / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014990:Xylans / Q000737:chemistry*
chemical_list: D025942:Oligosaccharides, Branched-Chain; D014990:Xylans; D010504:Periodic Acid; C085118:arabinoxylan; C009288:metaperiodate