Sugar-beet pulp was de-esterified and submitted to 72 h hydrolysis by 0.1 M HCl at 80°C. Oligomers containing a single glucuronic acid (GlcA) moiety in addition to n(≥ 2) repeats of the dimer →4)-α-D-GalpA-(1→2)-α-LRhap-(1→ were isolated from the hydrolysate by ion-exchange and gel-permeation. Glycosyl linkage composition analysis and 1H NMR studies indicated that the GlcA was attached to O-3 of a galacturonic acid (GalA) residue, as shown for the two pentamers β-D-GlcpA-(1→)-α-D-GalpA-(1→2)-α-L-Rhap-(1→4)-α-DGalpA-(1→2)-L-Rhap and α-D-GalpA-(1→2)-α-L-Rhap-(1→4)-[β-D-GlcpA-(1→3)]-α-D-GalpA-(1→2)-L-Rhap. Substitution by GlcA was estimated as occurring on one Gala residue out of 72 in the rhamnogalacturonan fraction of the backbone of beet pectins.
glucuronic acid, sugar beet, rhamnogalacturonan, pectin
NCBI PubMed ID: 10561599Publication DOI: 10.1046/j.1432-1327.1999.00896.xJournal NLM ID: 0107600Publisher: Oxford, UK: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
Correspondence: Renard CMGC
Institutions: Unité de Recherches sur les Polysaccharides, leurs Organisations et Interactions, Institut National de la Recherche Agronomique, Centre de Recherche Agro-Alimentaire de Nantes, Nantes, France
Methods: 1H NMR, GLC, HPAEC, GPC, ion-exchange chromatography, acetylation, TOCSY, methylation analysis, dialysis, NOESY, HOHAHA, HCl hydrolysis, TFA hydrolysis, DFQ-COSY, reduction with LiBDEt3
Found