Structural characteristics of water-soluble polysaccharides from Norway spruce (Picea abies)

Arabinogalactan proteins and pectic polysaccharides were isolated from greenery of Picea abies by water extraction. Main elements of their structure were determined by ion-exchange chromatography, partial acid and enzymatic hydrolysis, and NMR spectroscopy. It was established that the backbone of pectin macromolecules of greenery of P. abies is represented by segments of partially methyl-esterified and acetylated 1,4-α-d-galactopyranosyluronan, and partially 2-O- and/or 3-O-acetylated RG-I with side chains consisting of highly-branched 1,5-α-l-arabinan segments. The carbohydrate part of AGP of greenery of P. abies consists of AG-II, the main chain of which is represented by 1,3-β-d-Galp and 1,3,6-β-d-Galp residues. The side chains of AG-II are formed of 1,6- and 1,3,6-β-d-Galp, 1,3- and 1,5-α-l-Araf, β-d-GlcpA and 1,4-β-d-GlcpA, T-α-l-Araf, T-α-l-Rhap and T-α-l-Fucp residues. The AGPs of P. abies are also characterized by the presence of an unusual 4-O-Me-α-l-Fucp monosaccharide, which, as far as we know, was not found in pectins or AGP earlier.