Polysaccharide chain

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. 

Lysozyme is an enzyme that hydrolyzes polysaccharide chains. It ruptures certain bacterial cells by cleaving the polysaccharide chains that make up their cell wall. Lysozyme is found in many body fluids, but the most thoroughly studied form is from hen egg whites. The Russian scientist P. Laschtchenko first described the bacteriolytic properties of hen egg white lysozyme in 1909. In 1922, Alexander Fleming, the London bacteriologist who later discovered penicillin, gave the name lysozyme to the agent in mucus and tears that destroyed certain bacteria, because it was an enzyme that caused bacterial lysis. 

Double helix involving two polysaccharide chains. The helix is stabilised by intermolecular hydrogen bonds... 

IUPAC-IUB Joint Commission on Biochemical Nomenclature (JCBN), Symbols for specifying the conformation of polysaccharide chains (Recommendations 1981), Eur. J. Biochem, 131, 5-7, (1983) Pure Appl. Chem., 55,1269-1272 (1983) ref. 2, pp. 177-179. 

Fig. 1. — Schematic drawing of a hypothetical polysaccharide chain whose helix axis is along the c-edge of the unit cell.

X-Ray diffraction analysis of oriented polysaccharide fibers has had a long history. Marchessault and Sarko discussed this topic in Volume 22 of Advances, and a series of articles by Sundararajan and Marchessault in Volumes 33, 35, 36, and 40 surveyed ongoing developments. The comprehensive account presented here by Chandrasekaran (West Lafayette, Indiana) deals with some 50 polysaccharides, constituting a wide range of structural types, where accurate data and reliable interpretations are available. The regular helical structures of the polysaccharide chains, and associated cations and ordered water molecules, are presented in each instance as stereo drawings and discussed in relation to observed functional properties of the polymers. 

Investigations on biocompatible hydrogels based exclusively on polysaccharide chains were reported chitosan was linked with dialdehyde obtained from scleroglucan by controlled periodate oxidation [218]. The reaction took... 

Many bacterial polysaccharides contain phosphoric ester groups. There is a limited number of examples of monoesters. More common are phosphoric diesters, connecting an amino alcohol or an alditol to the polysaccharide chain. Another possibility is that oligosaccharide or oligosaccharide-alditol repeating units are connected to a polymer by phosphoric diester linkages. In addition to the intracellular teichoic acids, several bacteria, for example, different types of Streptococcus pneumoniae, elaborate extracellular polymers of this type. These polymers are generally discussed in connection with the bacterial polysaccharides. 

Figure 13-13. The glycogen molecule. A General structure. B Enlargement of structure at a branch point. The molecule is a sphere approximately 21 nm in diameter that can be visualized in electron micrographs. It has a molecular mass of 10 Da and consists of polysaccharide chains each containing about 13 glucose residues. The chains are either branched or unbranched and are arranged in 12 concentric layers (only four are shown in the figure). The branched chains (each has two branches) are found in the inner layers and the unbranched chains in the outer layer. (G, glycogenin, the primer molecule for glycogen synthesis.)...

Fig. 2.—Schematic Representation of the Heparin Proteoglycan. [The polysaccharide chains, bound to the polypeptide matrix through a linkage region," are cleaved by tissue endoglycosidases (arrows) after the transformations illustrated in Scheme 1.]...

Heparin is now recognized to be a mixture of polysaccharide chains of variable length and degree of heterogeneity. However, all of the heparin... 

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