Galactoglucomannan from the secondary cell wall of Picea abies L. Karst

The fine structural features of alkali-extracted galactoglucomannan composed of D-galactose, D-glucose and D-mannose in a 1:8:33 mole proportion from the secondary cell walls of Picea abies L. Karat have been determined. Compositional and methylation analyses of the polymer, partial acid hydrolysis, as well as H-1 and C-13 NMR measurements of the polymer and products of partial acid hydrolysis confirmed a beta-(1 --> 4)-linked backbone of galactoglucomannan containing the segments of mannosyl residues (Man(2), Man(3), Man(4), etc.) interrupted with the segments having both mannose and glucose residues, as well as the segments in which D-Glcp units can be adjacent to each other (Glc(2)). Further, the low content of branching points (similar to 3%) at the positions of O-6, O-3 and O-2 of mannosyl and O-6 and O-3 of glucosyl residues, but preferably of mannosyl ones, indicates the presence of short side-chains terminated at position O-6 predominantly by D-galactose units as single stubs. (C) 2000 Elsevier Science Ltd. All rights reserved.