Polysaccharide glycosaminoglycan

Analytical Techniques to Evaluate the Structure and Function of Natural Polysaccharides, Glycosaminoglycans, ed. N. Volpi, Research Signpost Trivandrum, India, 2002... 

Mammalian Polysaccharides Glycosaminoglycans (hyaluronic acid or hyaluronan, Chondroitin sulphate), gelatin and heparin sulfate, chitin and chitosan... 

Compounds with similar stmctures, ie, polysaccharide chains covalentiy attached to polypeptide chains, but where the polysaccharides are not glycosaminoglycans, are found commonly in plants and are known as protein-polysaccharides. 

For polysaccharides containing a substantial proportion of amino sugar residues, the term polysaccharide is adequate, although the term glycosaminoglycan may be used where particular emphasis is desired. 

Figure 13-14. Structure of some complex polysaccharides and glycosaminoglycans.

Among the spectroscopic methods applicable to polysaccharides, u.v. spectrophotometry is of little value for characterizing heparin, whose main, electronic chromophore (the C02 group) displays a band at 220 nm, that is, in a region where all glycosaminoglycans absorb (also through their N-acetyl chromophores), and where minor proportions of unsaturated or aromatic contaminants cause serious interference.77 With pure heparin preparations, the carboxylate chromophore is most useful for chiroptical measurements, and a semi-quantitative evaluation of the extent of N-acetylation of 2-amino-2-deoxy-D-glucose residues is also possible.78... 

Dermatan sulfate, also termed chondroitin sulfate B, a related glycosaminoglycan constituent of connective tissue, was known to be composed of galactosamine and a uronic acid, originally believed to be glucuronic acid but then claimed to be iduronic acid based largely on color reactions and paper chromatography. However, the d or L-enantiomer status of the latter monosaccharide was not clear. Jeanloz and Stoffyn unequivocally characterized the monosaccharide as L-iduronic acid by consecutive desulfation, reduction, and hydrolysis of the polysaccharide, followed by isolation of the crystalline 2,3,4-tri-0-acetyl-l,6-anhydro-/ -L-idopyranose, which was shown to be identical to an authentic specimen synthesized from 1,2-0-isopropylidene-/ -L-idofuranose.34... 

From the biological viewpoint, glycosaminoglycans (GAGS) are one of the most relevant oligo- and polysaccharides. The access to new NMR hardware and software, as well as the employment of new synthetic and molecular biology protocols have permitted important advances in the comprehension of their structural and conformational properties, as well as deeply study different examples of their interaction with receptors. 

We were successful earlier in achieving anioiuc/cationic complexes with glycosaminoglycans, e.g., hyaluronic acid/cationic polysaccharide compositions [44], now used in personal care applications. Those compositions are substantive, stable and user-friendly. Unfortunately, despite the highly anionic nature of hyaluronic acid (and other glycosaminoglycans), these materials do not block viral infections [39]. Furthermore, as shown by the in vivo rabbit irritation studies, such compositions displayed minimal irritation [13]. 

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