β-D-(1→4), β-D-(1→3) 'mixed linkage' xylans from red seaweeds of the order Nemaliales and Palmariales
| Autor: | Adriano G. Viana, Maria Eugênia R. Duarte, Alberto S. Cerezo, Alan G. Gonçalves, María C. Matulewicz, Miguel D. Noseda, Nair Yokoya |
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| Rok vydání: | 2010 |
| Předmět: |
Tricleocarpa fragilis
Galaxaura marginata chemistry.chemical_classification Magnetic Resonance Spectroscopy biology Optical Phenomena Stereochemistry Organic Chemistry Palmariales Tricleocarpa cylindrica Stereoisomerism General Medicine biology.organism_classification Polysaccharide Biochemistry Methylation Analytical Chemistry chemistry Palmaria palmata Botany Rhodophyta Carbohydrate Conformation Xylans Nemaliales Two-dimensional nuclear magnetic resonance spectroscopy |
| Zdroj: | Carbohydrate research. 346(8) |
| ISSN: | 1873-426X |
| Popis: | Xylans from five seaweeds belonging to the order Nemaliales ( Galaxaura marginata , Galaxaura obtusata , Tricleocarpa cylindrica , Tricleocarpa fragilis, and Scinaia halliae ) and one of the order Palmariales ( Palmaria palmata ) collected on the Brazilian coasts were extracted with hot water and purified from acid xylomannans and/or xylogalactans through Cetavlon precipitation of the acid polysaccharides. The β- d -(1→4), β- d -(1→3) ‘mixed linkage’ structures were determined using methylation analysis and 1D and 2D NMR spectroscopy. The presence of large sequences of β-(1→4)-linked units suggests transient aggregates of ribbon- or helical-ordered structures that would explain the low optical rotations. |
| Databáze: | OpenAIRE |
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