Some structural studies on the galactose-containing polysaccharide from bovine placenta
| Autor: | José H. Duarte, Roberto Pontarolo, M.A. Lacombe Feijó |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Placenta
Chemical Fractionation Biology Polysaccharide Galactans Methylation chemistry.chemical_compound Polysaccharides Pregnancy Animals Monosaccharide Glucans Glucan chemistry.chemical_classification Galactose Obstetrics and Gynecology Carbohydrate Galactan Hexosamines Reproductive Medicine Biochemistry chemistry Concanavalin A biology.protein Cattle Female Developmental Biology |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 0143-4004 |
| DOI: | 10.1016/s0143-4004(05)80464-3 |
| Popis: | Summary Polysaccharides were extracted from 8-month-old placenta with aqueous HgCl 2 . The protein-free material was purified by selective precipitation with Cetavlon in the presence of sodium borate at pH 8.5 and was homogeneous on molecular-sieve chromatography, electrophoresis, and on treatment with Concanavalin A. The preparation contained galactose and glucose as principal monosaccharides with 5 per cent of hexosamines. Methylation studies suggested that d -gluco and d -galactopyranosyl units may be constituents of glucan and galactan respectively which form a molecular aggregate that does not dissociate during the fractionation procedures. After treatment of the fraction with β-amylase, the proportion of glucose in the polysaccharide diminished, indicating the presence of (1→4)-linked α- d -glucopyranosyl residues. Also, when the fraction was treated with a crude protease having glucosidase activity a residual α- d -galactopyranan was isolated and found to contain non-reducing end-groups (30.0 per cent), 3-O-(39.5 per cent) and 3,6-di-O-substituted (30.5 per cent) units. The structure of the galactan was not modified according to methylation data, on removal of the glucosyl component. The polysaccharide fraction (pH 8.5 Cetavlon), isolated from bovine placenta, thus contains a glycogen-like material associated with a galactan as molecular aggregate. This galactan has not been previously recognized in bovine placenta and its occurrence in this organ supports the hypothesis that galactose-containing polysaccharides are involved in foetal development. |
| Databáze: | OpenAIRE |
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