Cell wall polysaccharides of Chinese Wolfberry ( Lycium barbarum): Part 2. Characterisation of arabinogalactan-proteins

• Published in: Carbohydrate polymers Vol. 84; no. 3; pp. 1075 - 1083
• Main Authors: Redgwell, Robert J., Curti, Delphine, Wang, Juankuan, Dobruchowska, Justyna M., Gerwig, Gerrit J., Kamerling, Johannis P., Bucheli, Peter
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 17.03.2011; Elsevier
• Subjects: anion exchange chromatography; Applied sciences; Arabinogalactan-proteins; arabinose; Biological and medical sciences; Cell wall polysaccharides; cell walls; Chemical constitution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; galactose; Goji berries; hydrophobicity; hydroxyproline; Lycium barbarum; Natural polymers; nuclear magnetic resonance spectroscopy; Physicochemistry of polymers; Plant physiology and development; polysaccharides; Starch and polysaccharides; Wolfberry; Cell wall polysaccharides; Arabinogalactan-proteins; Wolfberry; Goji berries; Lycium barbarum; Fruit; Molecular structure; Arabinogalactan; Experimental study; Protein; Dicotyledones; Angiospermae; Plant origin; Oside polymer; Spermatophyta; Chemical composition; Solanaceae
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2010.12.071

Arabinogalactan-proteins (AGPs) were isolated from Wolfberry fruit ( Lycium barbarum) and purified by anion-exchange chromatography and precipitation with Yariv reagent. Linkage and NMR analysis established the structure of Wolfberry AGP as typical of AGP reported from other sources. The data were consistent with a backbone of (1 → 3)-linked β- d-galactopyranosyl residues, many of which were substituted at O-6 with side chains of mainly 5-substituted α- l-arabinofuranosyl residues, terminated with α-(and β-) l-arabinofuranosyl, α- l-rhamnopyranosyl and β- d-glucopyranosyluronic acid residues. An unusual structural feature of the AGP was the occurrence of 4-substituted β- d-glucopyranosyluronic acid residues in the side chains. The AGP, which had a MW average of between 50 and 60 kDa, displayed heterogeneity with regard to both galactose/arabinose ratio and degree of branching. Protein accounted for ∼6% of the AGP and was rich in hydroxyproline. Evidence for an interaction between some of the AGP and hydrophobic moieties is presented.