Monosaccharides nonreducing sugars

Oxidation of Monosaccharides Reducing Sugars 1117 23-11 Nonreducing Sugars Formation of Glycosides 1119 23-12 Ether and Ester Formation 1121... 

There are many publications and comprehensive handbooks on the thin-layer chromatography (TLC) of carbohydrates (e.g., Refs. 1 and 2). The reason is their great importance in life science and the great diversity of cases monosaccharide, disaccharide, trisaccharide, oligosaccharide, polysaccharide, aldose, ke-tose, triose, tetrose, pentose, hexose, as well as reducing and nonreducing sugars. In addition, when extracted from natural products or produced by fermentation, carbohydrates are accompanied by many impurities. That is why separation methods are used predominantly for their analysis. 

Lysosomal enzymes specific for each monosaccharide remove sugars sequentially from the nonreducing ends of the chains. 

The ring forms (furanose or pyranose) of a monosaccharide can, to a limited extent, be inferred from the stability of the sugar to acid hydrolysis. The rates of hydrolysis of furanosides may be 10—10 times greater than those of the corresponding pyranosides (Aspinall, 1973). Terminal, nonreducing sugars can be characterized by methylation analysis as... 

Because the anomeric carbons of both the glucopyranose and fructofuranose units are involved in formation of the glycosidic bond, neither monosaccharide unit is in equilibrium with its open-chain form. Thus, sucrose is a nonreducing sugar. 

The monosaccharide unit on the left is the a-D-galactopyranosyl portion of sucrose. It is linked by a (1,2 ) gly-cosidic bond to P-D-fructofuranose. Thus, the anomeric carbons of the monomers are hnked by a glycosidic bond. Sucrose is an acetal. Therefore, it is a nonreducing sugar. 

The list of the most common monosaccharide components of bacterial polysaccharides, shown in Table VI, includes the sugars that were found at the nonreducing end of nine or more different disaccharide fragments of the polymers. The right-hand column of the Table, which shows the total number of such fragments, gives an estimate of the number of different glycosyltransferases that use the activated form of the monosaccharides as... 

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