title: Location of the O-acetyl substituents on a nonasaccharide repeating unit of sycamore extracellular xyloglucan.
abstract: The locations of the O-acetyl substituents on the major nonasaccharide repeating unit of the xyloglucan isolated from sycamore extracellular polysaccharides were determined by a combination of analytical methods, including f.a.b.-m.s. and 1H-n.m.r. spectroscopy. The O-2-linked-beta-D-galactosyl residue of the nonasaccharide was found to be the dominant site of O-acetyl substitution. Both mono-O-acetylated and di-O-acetylated beta-D-galactosyl residues were detected. The degree of O-acetylation of the beta-D-galactosyl residue, was estimated by 1H-n.m.r. spectroscopy to be 55-60% at O-6, 15-20% at O-4, and 20-25% at O-3. 1H-n.m.r. spectroscopy also indicated that approximately 50% of the beta-D-galactosyl residues are mono-O-acetylated, 25-30% are di-O-acetylated, and 20% are not acetylated.
authors: Complex Carbohydrate Research Center, University of Georgia, Athens 30613.
authors: W S
authors: WS
authors: York
authors: J E
authors: JE
authors: Oates
authors: H
authors: H
authors: van Halbeek
authors: A G
authors: AG
authors: Darvill
authors: P
authors: P
authors: Albersheim
authors: P R
authors: PR
authors: Tiller
authors: A
authors: A
authors: Dell
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005936:Glucans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis*; D010944:Plants / Q000032:analysis*; D011134:Polysaccharides; D014990:Xylans
chemical_list: D005936:Glucans; D009844:Oligosaccharides; D011134:Polysaccharides; D014990:Xylans; C029353:xyloglucan