Open AccessGlucuronic acid directly linked to galacturonic acid in the rhamnogalacturonan backbone of beet pectins
Author(s) -
Renard Catherine M. G. C.,
Crépeau MarieJeanne,
Thibault JeanFrançois
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00896.x
Subject(s) - hydrolysate , chemistry , hydrolysis , residue (chemistry) , glucuronic acid , moiety , dimer , acid hydrolysis , stereochemistry , polysaccharide , organic chemistry
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 ‐Gal p A‐(1→2)‐α‐ l ‐Rha p ‐(1→ were isolated from the hydrolysate by ion‐exchange and gel‐permeation. Glycosyl linkage composition analysis and 1 H 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 ‐Glc p A‐(1→3)‐α‐ d ‐Gal p A‐(1→2)‐α‐ l ‐Rha p ‐(1→4)‐α‐ d ‐Gal p A‐(1→2)‐ l ‐Rha p and α‐ d ‐Gal p A‐(1→2)‐α‐ l ‐Rha p ‐(1→4)‐[β‐ d ‐Glc p A‐(1→3)]‐α‐ d ‐Gal p A‐(1→2)‐ l ‐Rha p . Substitution by GlcA was estimated as occurring on one GalA residue out of 72 in the rhamnogalacturonan fraction of the backbone of beet pectins.