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Structural studies of the pectic polysaccharide from Siberian fir (Abies sibirica Ledeb.)

Makarova, Elena N., Patova, Olga A., Shakhmatov, Evgeny G., Kuznetsov, Sergey P., Ovodov, Yury S.
Carbohydrate polymers 2013 v.92 no.2 pp. 1817-1826
Abies sibirica, acid hydrolysis, esters, hydrochloric acid, ion exchange chromatography, nuclear magnetic resonance spectroscopy, pH, polysaccharides, sugars, wood
The pectic polysaccharide named abienan AS-A was isolated from the wood greenery of Abies sibirica using dilute hydrochloric acid (pH 4.0) at 70°C. The structure of abienan AS-A was elucidated using sugar composition analysis, ion-exchange chromatography and partial acid hydrolysis followed by NMR spectroscopy. The linear region of abienan AS-A was shown to contain linear 1,4-α-d-galactopyranosyluronan partially substituted with methyl esters or 3-O-acetyl groups and rhamnogalacturonan blocks consisting of 1,4-α-d-galacturonan partially substituted with methyl ester groups and connected by 2-O-substituted α-rhamnopyranose residues. The branched region of abienan AS-A was found to be made of RG-I. The side chains of RG-I were shown to contain 1,4-β-galactan and branched arabinan. Some 4-O-substituted β-galactopyranose residues were shown to be attached to the 4-position of the 2-O-substituted α-rhamnopyranose residues of the RG-I backbone. The arabinan groups were made up of a 1,5-linked α-l-arabinofuranan backbone that was 3-O-, 2-O-, and 2,3-di-O-substituted with the terminal and 1,3-linked α-l-arabinofuranose residues.