The conformation of the mucopolysaccharides. Hyaluronates.
Ontology highlight
ABSTRACT:
SUBMITTER: Atkins ED
PROVIDER: S-EPMC1174013 | biostudies-other | 1972 Aug
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Oriented films of the sodium salt of heparin crystallize in a triclinic unit cell. The X-ray diffraction results favour a tetrasaccharide covalent repeating sequence but the measured molecular repeat of 1.59nm is inconsistent with all alpha-(1-->4)(1ax-->4eq)-glycosidic linkages as generally accepted. Three models are proposed for the molecular shape of heparin, which depend on the chair conformation adopted by the hexuronic acid moieties. Model I has both uronic acids in the C1 chair form, model II has one uronic acid in each of the C1 and 1C chairs and model III has both in the 1C chair form. The merits of these models are discussed.
| S-EPMC1165889 | biostudies-other
Project description:Tendinopathy is an overuse tendon injury that occurs in loaded tendons and results in pain and functional impairment. Although many treatments for painful tendons are described, the scientific evidence for most of the conservative and surgical treatments is not always conclusive.This study was designed to evaluate the efficacy of 3 different interventions in patients with Achilles tendinopathy. The interventions include the combination of 2 physical therapy programs (eccentric training [EC] or passive stretching [PS]) with a supplement containing mucopolisaccharides. The efficacy of the interventions was evaluated depending on the stage of the disease.Fifty-nine patients were randomly assigned to 1 of 3 treatment groups, and classified according to the disease stage: reactive versus degenerative tendinopathy. Treatment groups were EC; EC + a dietary supplement containing mucopolisaccharides, type I collagen, and vitamin C (MCVC); and a passive stretching program + MCVC. Patients were evaluated at baseline, 6 weeks, and 12 weeks with the Victorian Institute of Sports Assessment-Achilles questionnaire for function, a visual analog scale for pain, and ultrasound characterization for the evolution of tendon structure.A significant improvement in Victorian Institute of Sports Assessment-Achilles questionnaire score, pain at rest, and pain during activity were detected in all 3 treatment groups at 6 and 12 weeks' follow-up when compared with baseline. In patients with reactive tendinopathy, the reduction in pain at rest was greater in the groups who took the supplemental MCVC than in the EC alone group (P < 0.05).MCVC seems to be therapeutically useful for management of tendinopathies, providing some additional benefit to physical therapy. This is especially evident in early stages of the disease, when the tendon does not present severe matrix and vascular changes.NCT01691716.
| S-EPMC5198794 | biostudies-literature
Project description:1. Two polysaccharides were isolated from the interstitial matrix surrounding the photoreceptor cells of cattle retina. They were liberated from this region of the tissue in a soluble form after agitation of whole retinas in 0.9% sodium chloride. One, which comprises two-thirds of the polysaccharides present, is a hyaluronidase-sensitive ;half-sulphated' chondroitin sulphate containing uronic acid, galactosamine and sulphate in the molar proportions 1.27:1.0:0.54. The other is a hyaluronidase-resistant non-sulphated heteropolysaccharide for which the name sialoglycan is proposed. It contains galactose, glucosamine and sialic acid in the molar proportions 2.4:1.0:0.4. Both polysaccharides contain only small amounts of nitrogen in excess of the amount calculated from their amino sugar and sialic acid content. 2. A similar combination of mucopolysaccharides is associated with the pigment epithelial-cell layer but in quantities only one-fifth of those present in the adjacent matrix area. 3. The ease with which they are released into aqueous media is consistent with the assumption that they are present in the extracellular spaces in both of these tissue layers. 4. The retinal residue left after removal of the two soluble polysaccharides is rich in amino sugar- and sialic acid-containing polymers, which appear to be firmly bound to the tissue fragments. 5. About one-third of the sialic acid and one-tenth of the amino sugar could be extracted with chloroform-methanol. The components in this fraction were tentatively identified as gangliosides. 6. Digestion of the chloroform-methanol-insoluble residue with Pronase yielded as the principal product a heteropolysaccharide containing 16.5% of glucosamine, 24.3% of neutral sugar (galactose plus fucose) and 18.1% of sialic acid. This substance has been classified as a sialoglycan of composition similar to (but not identical with) that of the soluble one isolated from the matrix area of the tissue.
| S-EPMC1198771 | biostudies-other
Project description:1. The uptake of dilute neutral hypochlorite by epithelial mucopolysaccharides has been compared with that of proteins, polysaccharides, amino acids and sugars. The uptake has been shown to be related to the protein content of the mucopolysaccharides rather than their polysaccharide content. 2. The destruction of the components of epithelial mucopolysaccharides, certain sugars and polysaccharides after oxidation with dilute neutral hypochlorite at 0-4 degrees has been studied. Very little destruction of the sugar components occurred and in epithelial mucopolysaccharides the only amino acid destroyed specifically was arginine. 3. Oxidation of bovine submaxillary-gland mucoprotein and ovalbumin caused very little destruction of hexosamine and no detectable liberation of this residue as a free reducing group, indicating that the O-seryl galactosaminide and the N-acyl-glycosylamine linkages reported to be present in these compounds were relatively stable to hypochlorite. 4. Depolymerization of epithelial mucopolysaccharides by neutral hypochlorite has been studied by using gel-filtration columns and compared with the depolymerization of polysaccharides and proteins under similar conditions. The polysaccharides examined were relatively resistant to oxidation whereas the proteins were extensively broken down. It is inferred that the extensive depolymerization of epithelial mucopolysaccharides by hypochlorite is related to their protein content rather than their polysaccharide content. 5. Fractionation of the products of oxidation of epithelial mucopolysaccharides by column procedures has revealed that the relative proportions of components in all fractions were similar to those in the original material. 6. Though this study does not provide unequivocal evidence from which the overall structure of this type of epithelial mucopolysaccharide may be deduced, the balance of probabilities now appears to favour a long polypeptide chain to which a large number of oligosaccharide side chains are attached via O-seryl and O-threonyl glycosidic linkages. The results, however, are also consistent with an alternating sequence of short polysaccharide and polypeptide chains and further evidence is necessary before this structure can be ruled out.
| S-EPMC1264862 | biostudies-other
Project description:1. In view of the suggested association between collagen and acid mucopolysaccharides in the connective tissues, this study was designed to see whether the lathyrus factor, beta-aminopropionitrile, affected the acid mucopolysaccharides as well as inhibiting the normal polymerization of collagen. The changing pattern of these two components of cartilage from normal and lathyritic chick embryos aged 14-20 days is described. The chondroitin sulphates and their protein complexes have been isolated from these cartilages, characterized and compared, particularly with respect to their sulphate content; no significant differences in quality or quantity were detectable. 2. Saline extracts of normal and lathyritic cartilages were also compared; whereas the collagen content of lathyritic extracts was increased to ten times that in the normal, the acid mucopolysaccharide content of both extracts was always the same. 3. It therefore appears that in the chick embryo beta-aminopropionitrile does not affect the acid mucopolysaccharides of the developing cartilage.
| S-EPMC1270125 | biostudies-other
Project description:1. The mucopolysaccharide from the glands of Lorenzini of Squalus acanthias has been isolated and purified. 2. The material is a sulphated polysaccharide containing glucosamine, galactosamine, galactose and traces of an uronic acid. 3. This vertebrate polysaccharide is unusual in appearing to have both amino sugars present in the molecule. The amino sugars are N-acetylated. 4. This molecule is one of a group of related mucopolysaccharides which vary in composition with the animal species. The generic name ;lorenzan sulphates' is suggested to describe these substances.
| S-EPMC1270412 | biostudies-other
Project description:1. Glycosidic linkage of carbohydrate to the primary hydroxyl groups of threonine and serine has been established in human blood-group A and Le(a) substances, bovine submaxillary-gland mucin and human pseudomyxomatous mucin. 2. Treatment of these substances in 0.09n-lithium hydroxide at 100 degrees for 1hr. led to beta-elimination at these glycosidic linkages with the resultant formation of alpha-oxobutyric acid and glycine from threonine linkages, and pyruvic acid from serine linkages. Though most of the threonine was destroyed in every case, about one-third to one-half of the serine residues resisted alkaline cleavage. Such results, indicative of the presence of unbound serine residues, allow, in submaxillary mucin, for a close correlation between the remaining serine, threonine, glutamic acid and aspartic acid and the available sialyl-(2-->6)-N-acetylgalactosamine prosthetic groups. 3. The stoichiometry of the beta-eliminations has been demonstrated for pseudomyxomatous mucin. The alpha-oxo acids were separated and determined as their quinoxalinol derivatives by thin-layer chromatography on silica gel. Reaction at the threonine centres favoured alpha-oxobutyric acid formation (70%, via the intermediary dehydropeptide) over the alternative pathway to glycine (30%). 4. 100% of the hexosamine was destroyed in submaxillary-gland mucin, 85% in pseudomyxomatous mucin and about 60% in the blood-group substances. In the latter cases, the glucosamine/galactosamine ratio was increased from about 4:1 to 8-10:1, suggesting a preferential destruction of galactosamine. Evidence was obtained, however, for a further destruction of hexosamine, in addition to that which could be theoretically attached to peptide at possible known binding sites. 5. The major part of the alkali-resistant hexosamine in the blood-group substances was non-diffusible and was accompanied by the constituent carbohydrates in similar molar proportions to the native materials.
| S-EPMC1264646 | biostudies-other
Project description:1. The interaction of acid mucopolysaccharides of connective tissue with solubilized collagen of native, or near-native, structure was investigated by free solution electrophoresis at pH7.0. 2. Complex-formation was detected by the appearance of a third peak in the ascending limb only, indicating reversible association. 3. Complex-formation was destroyed by prior heating of solubilized collagen, indicating a probable requirement for high molecular weight or internal structure of the protein. 4. Hyaluronate and chondroitin sulphate of mol.wt. 50000 gave complexes with soluble collagen at I 0.4, whereas heparin and chondroitin sulphate of mol.wt. 15000-18000 did not. All mucopolysaccharides yielded complexes at I 0.1. The stability of the complex appears mainly dependent on electrostatic forces and is increased with increase in chain length of the polysaccharide. 5. Solubilized collagen interacted to yield gels with the ;native' chondroitin sulphate-protein macro-molecule from cartilage. 6. A schematic model for the interaction of collagen and chondroitin sulphate-protein macromolecules shows parallel-ordered interaction of collagen fibrils with chondroitin sulphate side chains of the chondroitin sulphate-protein macromolecule. The biological implications of this model are discussed, particularly in relation to the ordered structures and the ionic-network properties of the intercellular components of connective tissue.
| S-EPMC1207207 | biostudies-other
Project description:Proteoglycans of 300 000 mol.wt. were isolated from dispersed rat basophil tumour cells after labelling of the sulphated mucopolysaccharides with 35S in vitro:90% of the 35S-labelled mucopolysaccharides were extracted at high salt concentration. Alkali degradation of the 35S-labelled proteoglycans yielded glycosaminoglycan chains of 40 000 mol.wt. The composition of the salt-extracted 35S-labelled mucopolysaccharides, as defined by parallel or sequential degradation with chondroitinase AC, chondroitinase ABC and heparinase and resolution of the disaccharide-digestion products obtained with chondroitinase AC, was 48--61% chondroitin 4-sulphate, 20--30% dermatan sulphate, 10--15% heparin and 7--9% chondroitin 6-sulphate. Most of the salt-extracted 35S-labelled mucopolysaccharides were highly charged, with heparin and chondroitin 6-sulphate being relatively uniform in this regard, whereas chondroitin 4-sulphate and dematan sulphate exhibited a range of charge characteristics. The diversity of sulphated mucopolysaccharides present in the rat leukaemic basophil is in contrast with the predominance of heparin in the rat mast cell.
| S-EPMC1161362 | biostudies-other
Project description:The relationship between the three-dimensional structures of oligosaccharides and polysaccharides and their biological properties has been the focus of many recent studies. The overall conformation of an oligosaccharide depends primarily on the orientation of the torsion angles (phi, psi, and omega) between glycosyl residues. Numerous experimental studies have shown that in glucopyranosides the omega-torsion angle (O(6)-C(6)-C(5)-O(5)) displays a preference for gauche orientations, in disagreement with predictions based on gas-phase quantum mechanics calculations. In contrast, the omega-angle in galactopyranosides displays a high proportion of the anti-orientation. For oligosaccharides containing glycosidic linkages at the 6-position (1-->6 linked), variations in rotamer population have a direct effect on the oligosaccharides' structure and function, and yet the physical origin of these conformational preferences remains unclear. Although it is generally recognized that the gauche effect in carbohydrates is a solvent-dependent phenomenon, the mechanism through which solvent induces the gauche preference is not understood. In the present work, quantum mechanics and solvated molecular dynamics calculations were performed on two representative carbohydrates, methyl alpha-D-glucopyranoside and methyl alpha-D-galactopyranoside. We show that correct reproduction of the experimental rotamer distributions about the omega-angles is obtained only after explicit water is included in the molecular dynamics simulations. The primary role of the water appears to be to disrupt the hydrogen bonding within the carbohydrate, thereby allowing the rotamer populations to be determined by internal electronic and steric repulsions between the oxygen atoms. The results reported here provide a quantitative explanation of the conformational behavior of (1-->6)-linked carbohydrates.
| S-EPMC58501 | biostudies-literature