title: Structural characterization of a glucuronoarabinoxylan from pineapple (Ananas comosus (L.) Merrill) gum exudate.
abstract: Native polysaccharide from pineapple gum (PANP) was obtained following alkaline extraction of gum and fractionation with cetylpyridinium chloride. It was characterized as a glucuronoarabinoxylan using NMR, methylation data, controlled Smith degradation, carboxy-reduction, and ESI-MS of oligosaccharides produced on mild acid hydrolysis of PANP. HSPEC-MALLS-RI of carboxy-reduced fraction showed homogeneous profile (Mw 1.943×10(5) g/mol). PANP was composed of Ara, Xyl, Gal, and GlcpA (40:23:7:30 molar ratio). Its main chain presented (1→4)-linked β-xylan, highly substituted at O-2 and O-3 by side chains of 3-O- and 3,5-di-O-linked α-Araf, 2-O- and 4-O-linked α-GlcpA, and nonreducing end-units of α-Araf, β-Arap, β-Galp, and α-GlcpA. ESI-MS of a mixture of oligosaccharides formed on the mild acid hydrolysis of PANP was consistent with repetitive structures of α-GlcpA O-3 linked at β-Xylp units, whereas in others glucuronoarabinoxylan-type gum exudates, α-GlcpA units had been previously found to be linked at O-2.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, UFPR, CP 19046, CEP 81531-990, Curitiba, PR, Brazil.
authors.forename: Fernanda F
authors.initials: FF
authors.lastname: Simas-Tosin
authors.forename: Lauro M
authors.initials: LM
authors.lastname: de Souza
authors.forename: Ricardo
authors.initials: R
authors.lastname: Wagner
authors.forename: Graciele C Z
authors.initials: GC
authors.lastname: Pereira
authors.forename: Ruth R
authors.initials: RR
authors.lastname: Barraza
authors.forename: Cinthia F
authors.initials: CF
authors.lastname: Wendel
authors.forename: Guilherme L
authors.initials: GL
authors.lastname: Sassaki
authors.forename: Marcello
authors.initials: M
authors.lastname: Iacomini
authors.forename: Philip A J
authors.initials: PA
authors.lastname: Gorin
mesh_terms: D031230:Ananas / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002594:Cetylpyridinium / Q000737:chemistry; D005590:Fractional Precipitation; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010084:Oxidation-Reduction; D053149:Plant Gums / Q000737:chemistry* / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization; D014990:Xylans / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D053149:Plant Gums; D014990:Xylans; C114470:glucuronoarabinoxylan; D002594:Cetylpyridinium