The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos

The endosperm of the seed of Gleditsia triacanthos contains 4.8% of 85% ethanol-soluble, galactomannan-like oligosaccharides having Man:Gal ratios of 1.5-2.6:1 and an average degree of polymerization of 15. They have a narrow distribution of molecular weights and of ratio of components. The oligosac...

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Autores principales: Manzi, A.E., Cerezo, A.S.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00086215_v134_n1_p115_Manzi
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00086215_v134_n1_p115_Manzi2023-10-03T14:06:19Z The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos Manzi, A.E. Cerezo, A.S. The endosperm of the seed of Gleditsia triacanthos contains 4.8% of 85% ethanol-soluble, galactomannan-like oligosaccharides having Man:Gal ratios of 1.5-2.6:1 and an average degree of polymerization of 15. They have a narrow distribution of molecular weights and of ratio of components. The oligosaccharides have the gross structure accepted for the galactomannans, namely, a β-(1→4)-linked d-mannopyranosyl backbone having single stubs of α-(1→6)-linked d-galactopyranosyl groups. Some of the lateral chains contain more than one unit, and a minor proportion of the branches are ended by arabinofuranose or fucopyranose residues. Unusual branching points formed by 3,4-linked d-mannosyl, or 3,6-linked d-galactosyl units, or both, were also found. Despite their low molecular weight, the oligosaccharides form aggregates with a structure similar to that of the aggregates of the related galactomannans, but having a lower association energy. This fact, together with the difficulty of combining with more than one partner (due to the short, central chain), results in an increased solubility and in nonviscous solutions. The 13C-n.m.r. spectrum differentiated clearly the five structural units of the oligosaccharides, namely, the reducing and nonreducing end-chains of the d-mannosyl backbone; substituted and nonsubstitued, internal β-(1→4)-linked mannopyranosyl units of the backbone; and the galactosyl nonreducing end-chain of the lateral chains. The C-4 signal of the (1→4)-linked d-mannose and the C-6 signal of the same, but substituted, units showed splitting into three lines. The first has been attributed to sequence-related heterogeneity, whereas the latter is tentatively explained by assuming that this resonance is sensitive to whether the mannosyl units linked to that residue are also branched, or not. © 1984. Fil:Manzi, A.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Cerezo, A.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00086215_v134_n1_p115_Manzi
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description The endosperm of the seed of Gleditsia triacanthos contains 4.8% of 85% ethanol-soluble, galactomannan-like oligosaccharides having Man:Gal ratios of 1.5-2.6:1 and an average degree of polymerization of 15. They have a narrow distribution of molecular weights and of ratio of components. The oligosaccharides have the gross structure accepted for the galactomannans, namely, a β-(1→4)-linked d-mannopyranosyl backbone having single stubs of α-(1→6)-linked d-galactopyranosyl groups. Some of the lateral chains contain more than one unit, and a minor proportion of the branches are ended by arabinofuranose or fucopyranose residues. Unusual branching points formed by 3,4-linked d-mannosyl, or 3,6-linked d-galactosyl units, or both, were also found. Despite their low molecular weight, the oligosaccharides form aggregates with a structure similar to that of the aggregates of the related galactomannans, but having a lower association energy. This fact, together with the difficulty of combining with more than one partner (due to the short, central chain), results in an increased solubility and in nonviscous solutions. The 13C-n.m.r. spectrum differentiated clearly the five structural units of the oligosaccharides, namely, the reducing and nonreducing end-chains of the d-mannosyl backbone; substituted and nonsubstitued, internal β-(1→4)-linked mannopyranosyl units of the backbone; and the galactosyl nonreducing end-chain of the lateral chains. The C-4 signal of the (1→4)-linked d-mannose and the C-6 signal of the same, but substituted, units showed splitting into three lines. The first has been attributed to sequence-related heterogeneity, whereas the latter is tentatively explained by assuming that this resonance is sensitive to whether the mannosyl units linked to that residue are also branched, or not. © 1984.
format JOUR
author Manzi, A.E.
Cerezo, A.S.
spellingShingle Manzi, A.E.
Cerezo, A.S.
The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos
author_facet Manzi, A.E.
Cerezo, A.S.
author_sort Manzi, A.E.
title The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos
title_short The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos
title_full The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos
title_fullStr The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos
title_full_unstemmed The galactomannan-like oligosaccharides from the endosperm of the seed of Gleditsia triacanthos
title_sort galactomannan-like oligosaccharides from the endosperm of the seed of gleditsia triacanthos
url http://hdl.handle.net/20.500.12110/paper_00086215_v134_n1_p115_Manzi
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