Comparison of the structures of hybrid κ-/β-carrageenans extracted from Furcellaria lumbricalis and Tichocarpus crinitus

kappa-beta-Carrageenans extracted from Furcellaria lumbricalis and Tichocarpus crinitus are hybrid polysaccharides that have roughly similar kappa- and beta-carrabiose contents. The distributions of these carrabiose moieties were compared using gel permeation chromatography to analyse the end-products obtained after degradation with Pseudoalteromonas carrageenovora kappa-carrageenase. Three fractions were obtained: standard oligo-kappa-carrageenans, hybrid oligo-kappa-/beta-carrageenans and an enzyme-resistant fraction. The structure of the most abundant hybrid oligo-kappa-/beta-carrageenans and the composition of the kappa-/beta-fractions resistant to degradation were determined by H-1 NMR. Altogether, the results suggest that the kappa- and beta-carrabiose moieties in F. lumbricalis are more randomly distributed than in T. crinitus carrageenan, which has a more regular block-type distribution. (C) 2011 Elsevier Ltd. All rights reserved.