No abstract

A cold-water-soluble wheat-endosperm arabinoxylan consisting of a backbone of (l-+4)-linked B-D-xylopyranosyl residues that are variously unsubstituted, and 3-or 2,3_substituted with single a-r.-arabinofuranosyl groups, was subjected to 'H-n.m.r. spectroscopy. The results of 2D homonuclear Hartmann-Hahn and 1D 'H-n.m.r. spectroscopy allowed the identification of 3-and 2,3-substituted xylose residues, each with adjacent unsubstituted xylose residues, and also substituted xylose residues with a substituted xylose residue as a neighbour. The 'H-n.m.r. data were correlated with 13C-n.m.r. data by means of a 13C-'H 2D proton-detected heteronuclear multiple-quantum correlation experiment, which showed that only different types of branching (i.e., 3-and 2,3-) can be identified by the "C-n.m.r. data.

No abstract

The structures of hepta-to tetradeca-saccharides, generated by digestion of wheat-endospenn arabinoxylan with endo-(I +4)-B-o-xylanase, and isolated by gel-permeation chromatography on Bio-Gel P-6 and high-performance anion-exchange chromatography with pulsed amperometric detection (h.p.a.e. . elution pattern showed that these combinations are not present in equal amounts. Also, compounds containing two 2,3-branched P-D-Xylp residues separated by one or two unbranched P-D-Xylp residues were found, and the presence of a tetradecasaccharide containing three 2,3-branched /I-D-Xylp residues was established.

No abstract