1 H-N.m.r. spectral assignments for two series of heparin-derived oligosaccharides
| Autor: | Peter G.W. Gettins, Angela Horne |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Magnetic Resonance Spectroscopy
Anomer Proton Iduronic Acid Stereochemistry Glucuronate Molecular Sequence Data Disaccharide Oligosaccharides Glucuronates Disaccharides Biochemistry Analytical Chemistry chemistry.chemical_compound Glucuronic Acid Glucosamine Heparin Organic Chemistry Resonance General Medicine Nuclear magnetic resonance spectroscopy HEXA Carbohydrate Sequence chemistry Trisaccharides |
| Zdroj: | Carbohydrate Research. 225:43-57 |
| ISSN: | 0008-6215 |
| Popis: | Six heparin-derived oligosaccharides, ranging in size from di- to octa-saccharide and forming two closely related series different in structure by the substitution of an unsulfated d -glucuronate for a 2-sulfated l -iduronate residue, have been characterized by 2-dimensional 1 H-n.m.r. spectroscopy. In addition to providing new data on hexa- and octa-saccharides, several important changes to previously published data have been found for the two tetrasaccharides. The d -glucuronic acid H-5 proton is assigned to a resonance in the same region as resonances for the H-3 and H-4 d -glucuronate protons, rather than downfield from these resonances as earlier reported. The presence of d -glucuronic acid in the heparin sequence of the series-1 fragments affects the positions of neighboring d -glucosamine resonances, in particular shifting the anomeric proton signal in the preceding d -glucosamin 0.1–0.2 p.p.m. downfield. Resonances from the reducing-end d -glucosamines differ from internal d -glucosamine resonances both in relative position and in the degree of chemical shift difference between the H-6 and H-6′ protons. This work illustrates the usefulness of two-dimensional techniques in determining heparin structure and emphasizes the need for direct analysis, rather than assignment by comparison to model compounds. |
| Databáze: | OpenAIRE |
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