The system of galactans from Cryptonemia crenulata (Halymeniaceae, Halymeniales) and the structure of two major fractions. Kinetic studies on the alkaline cyclization of the unusual diad G2S→D(L)6S
Cryptonemia crenulata biosynthesizes a family of dl-hybrid galactans that are based on the classical 3-linked β-d-galactopyranosyl→4-linked α-galactopyranosyl alternating sequence (A-units→B-units). The dispersion of structures in these galactans is based on four factors, namely: (a) the amount and...
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todo:paper_00086215_v340_n4_p711_Zibetti2023-10-03T14:07:09Z The system of galactans from Cryptonemia crenulata (Halymeniaceae, Halymeniales) and the structure of two major fractions. Kinetic studies on the alkaline cyclization of the unusual diad G2S→D(L)6S Zibetti, R.G.M. Noseda, M.D. Cerezo, A.S. Duarte, M.E.R. Chemical structure Cryptonemia crenulata Halymeniales Kinetic studies Methylation analysis NMR spectroscopy Seaweed Sulfated galactans Biosynthesis Dispersions Molecular structure Rate constants Sugars Alkali treatment Galactans Pyruvic acid ketals Polysaccharides 3,6 anhydrogalactose alkali alpha galactose 2,6 sulfate alpha galactose 6 sulfate carrageenan galactan galactose porphyrin derivative pyruvic acid derivative sulfate unclassified drug xylose article biosynthesis carbohydrate analysis carbohydrate synthesis chemical reaction kinetics controlled study cryptonemia crenulata dispersion hybrid nonhuman precursor priority journal quantitative analysis reaction analysis seaweed sequence analysis structure analysis Algae, Red Chromatography, Ion Exchange Cyclization Galactans Hydroxides Kinetics Methylation Nuclear Magnetic Resonance, Biomolecular Spectroscopy, Fourier Transform Infrared algae Cryptonemia crenulata Halymeniaceae Halymeniales Cryptonemia crenulata biosynthesizes a family of dl-hybrid galactans that are based on the classical 3-linked β-d-galactopyranosyl→4-linked α-galactopyranosyl alternating sequence (A-units→B-units). The dispersion of structures in these galactans is based on four factors, namely: (a) the amount and position of substituent groups as sulfate (major), pyruvic acid ketals, methoxyl and side substituents of β-d-xylose and/or β-d-galactose; (b) the ratio galactose/3,6-anhydrogalactose in the B-units; (c) the ratio d-/l-galactoses and 3,6-anhydrogalactoses also in the B-units and (d) the sequence of the diads in the linear backbone. Alkali treatment carried out on the major fraction produced a nearly quantitative formation of 3,6-anhydrogalactose units from precursor units (α-galactose 6-sulfate (major) and α-galactose 2,6-sulfate, minor). Kinetic studies show a rate constant, for the diad G2S-D(L) 6-S, of 1.7 × 104 s -1 indicating a reaction faster than in λ-carrageenans but slower than in porphyrans. © 2005 Elsevier Ltd. All rights reserved. Fil:Noseda, M.D. 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_v340_n4_p711_Zibetti |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Chemical structure Cryptonemia crenulata Halymeniales Kinetic studies Methylation analysis NMR spectroscopy Seaweed Sulfated galactans Biosynthesis Dispersions Molecular structure Rate constants Sugars Alkali treatment Galactans Pyruvic acid ketals Polysaccharides 3,6 anhydrogalactose alkali alpha galactose 2,6 sulfate alpha galactose 6 sulfate carrageenan galactan galactose porphyrin derivative pyruvic acid derivative sulfate unclassified drug xylose article biosynthesis carbohydrate analysis carbohydrate synthesis chemical reaction kinetics controlled study cryptonemia crenulata dispersion hybrid nonhuman precursor priority journal quantitative analysis reaction analysis seaweed sequence analysis structure analysis Algae, Red Chromatography, Ion Exchange Cyclization Galactans Hydroxides Kinetics Methylation Nuclear Magnetic Resonance, Biomolecular Spectroscopy, Fourier Transform Infrared algae Cryptonemia crenulata Halymeniaceae Halymeniales |
| spellingShingle |
Chemical structure Cryptonemia crenulata Halymeniales Kinetic studies Methylation analysis NMR spectroscopy Seaweed Sulfated galactans Biosynthesis Dispersions Molecular structure Rate constants Sugars Alkali treatment Galactans Pyruvic acid ketals Polysaccharides 3,6 anhydrogalactose alkali alpha galactose 2,6 sulfate alpha galactose 6 sulfate carrageenan galactan galactose porphyrin derivative pyruvic acid derivative sulfate unclassified drug xylose article biosynthesis carbohydrate analysis carbohydrate synthesis chemical reaction kinetics controlled study cryptonemia crenulata dispersion hybrid nonhuman precursor priority journal quantitative analysis reaction analysis seaweed sequence analysis structure analysis Algae, Red Chromatography, Ion Exchange Cyclization Galactans Hydroxides Kinetics Methylation Nuclear Magnetic Resonance, Biomolecular Spectroscopy, Fourier Transform Infrared algae Cryptonemia crenulata Halymeniaceae Halymeniales Zibetti, R.G.M. Noseda, M.D. Cerezo, A.S. Duarte, M.E.R. The system of galactans from Cryptonemia crenulata (Halymeniaceae, Halymeniales) and the structure of two major fractions. Kinetic studies on the alkaline cyclization of the unusual diad G2S→D(L)6S |
| topic_facet |
Chemical structure Cryptonemia crenulata Halymeniales Kinetic studies Methylation analysis NMR spectroscopy Seaweed Sulfated galactans Biosynthesis Dispersions Molecular structure Rate constants Sugars Alkali treatment Galactans Pyruvic acid ketals Polysaccharides 3,6 anhydrogalactose alkali alpha galactose 2,6 sulfate alpha galactose 6 sulfate carrageenan galactan galactose porphyrin derivative pyruvic acid derivative sulfate unclassified drug xylose article biosynthesis carbohydrate analysis carbohydrate synthesis chemical reaction kinetics controlled study cryptonemia crenulata dispersion hybrid nonhuman precursor priority journal quantitative analysis reaction analysis seaweed sequence analysis structure analysis Algae, Red Chromatography, Ion Exchange Cyclization Galactans Hydroxides Kinetics Methylation Nuclear Magnetic Resonance, Biomolecular Spectroscopy, Fourier Transform Infrared algae Cryptonemia crenulata Halymeniaceae Halymeniales |
| description |
Cryptonemia crenulata biosynthesizes a family of dl-hybrid galactans that are based on the classical 3-linked β-d-galactopyranosyl→4-linked α-galactopyranosyl alternating sequence (A-units→B-units). The dispersion of structures in these galactans is based on four factors, namely: (a) the amount and position of substituent groups as sulfate (major), pyruvic acid ketals, methoxyl and side substituents of β-d-xylose and/or β-d-galactose; (b) the ratio galactose/3,6-anhydrogalactose in the B-units; (c) the ratio d-/l-galactoses and 3,6-anhydrogalactoses also in the B-units and (d) the sequence of the diads in the linear backbone. Alkali treatment carried out on the major fraction produced a nearly quantitative formation of 3,6-anhydrogalactose units from precursor units (α-galactose 6-sulfate (major) and α-galactose 2,6-sulfate, minor). Kinetic studies show a rate constant, for the diad G2S-D(L) 6-S, of 1.7 × 104 s -1 indicating a reaction faster than in λ-carrageenans but slower than in porphyrans. © 2005 Elsevier Ltd. All rights reserved. |
| format |
JOUR |
| author |
Zibetti, R.G.M. Noseda, M.D. Cerezo, A.S. Duarte, M.E.R. |
| author_facet |
Zibetti, R.G.M. Noseda, M.D. Cerezo, A.S. Duarte, M.E.R. |
| author_sort |
Zibetti, R.G.M. |
| title |
The system of galactans from Cryptonemia crenulata (Halymeniaceae, Halymeniales) and the structure of two major fractions. Kinetic studies on the alkaline cyclization of the unusual diad G2S→D(L)6S |
| title_short |
The system of galactans from Cryptonemia crenulata (Halymeniaceae, Halymeniales) and the structure of two major fractions. Kinetic studies on the alkaline cyclization of the unusual diad G2S→D(L)6S |
| title_full |
The system of galactans from Cryptonemia crenulata (Halymeniaceae, Halymeniales) and the structure of two major fractions. Kinetic studies on the alkaline cyclization of the unusual diad G2S→D(L)6S |
| title_fullStr |
The system of galactans from Cryptonemia crenulata (Halymeniaceae, Halymeniales) and the structure of two major fractions. Kinetic studies on the alkaline cyclization of the unusual diad G2S→D(L)6S |
| title_full_unstemmed |
The system of galactans from Cryptonemia crenulata (Halymeniaceae, Halymeniales) and the structure of two major fractions. Kinetic studies on the alkaline cyclization of the unusual diad G2S→D(L)6S |
| title_sort |
system of galactans from cryptonemia crenulata (halymeniaceae, halymeniales) and the structure of two major fractions. kinetic studies on the alkaline cyclization of the unusual diad g2s→d(l)6s |
| url |
http://hdl.handle.net/20.500.12110/paper_00086215_v340_n4_p711_Zibetti |
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