title: New 4-O-substituted xylosyl units in the xyloglucan from leaves of Hymenaea courbaril.
abstract: A homogeneous fucogalactoxyloglucan, isolated from the leaves of Hymenaea courbaril, was analysed by methylation-GC-MS. These procedures involved derived partially O-methylated alditol acetates and acetylated aldononitriles, which demonstrated the presence of both 2-O- and 4-O-substituted Xylp units in the side-chains. The presence of the unusual, latter structure was confirmed by 2D NMR spectroscopy with a correlated HMQC C-4/H-4 signal at delta 77.8/3.73. A similar 4-O-substituted xylosyl structure was present in a decasaccharide Glc4Xyl3Gal2Fuc obtained via endo-glucanase treatment of the polysaccharide, which gave rise to a molecular ion with m/z 1555 (ESI-MS, Na+ form).
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19046, 81531-990 Curitiba, Paraná, Brazil.
authors.forename: A P
authors.initials: AP
authors.lastname: Busato
authors.forename: C G
authors.initials: CG
authors.lastname: Vargas-Rechia
authors.forename: P A J
authors.initials: PA
authors.lastname: Gorin
authors.forename: C L
authors.initials: CL
authors.lastname: Petkowicz
authors.forename: C A
authors.initials: CA
authors.lastname: Tischer
authors.forename: R
authors.initials: R
authors.lastname: Bochicchio
authors.forename: F
authors.initials: F
authors.lastname: Reicher
mesh_terms: D002240:Carbohydrate Sequence; D002480:Cellulase / Q000378:metabolism; D007887:Fabaceae / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D005936:Glucans / Q000737:chemistry*; D008745:Methylation; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D014990:Xylans / Q000737:chemistry*
chemical_list: D005936:Glucans; D014990:Xylans; D002480:Cellulase