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

The fine structural features of alkali-extracted galactoglucomannan composed of d-galactose, d-glucose and d-mannose in a 1:8:33 mol proportion from the secondary cell walls of Picea abies L. Karst have been determined. Compositional and methylation analyses of the polymer, partial acid hydrolysis, as well as 1H and 13C NMR measurements of the polymer and products of partial acid hydrolysis confirmed a β-(1→4)-linked backbone of galactoglucomannan containing the segments of mannosyl residues (Man2, Man3, Man4, 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 (Glc2). Further, the low content of branching points (∼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.