Polysaccharide structure Hydrolyze

Type IV Pneumococcus Specific Polysaccharide.—This capsular material110 ([ck]d + 33°, water) has been hydrolyzed and shown to contain units of D-glucose and N-acetyl-hexosamine. Its structure has not yet been studied. 

The simplest carbohydrate, called a monosaccharide, is composed of a structure that cannot be hydrolyzed to simpler polyhydroxylic compounds. A disaccharide is a carbohydrate that contains two of these basic units, and a polysaccharide contains many polyhydroxylic monomers. 

A bacterial phosphatidylinositol specific phospholipase C (PI-PLC) had been available for many years before it was demonstrated to strip a number of membrane-bound proteins from eukaryotic cell surfaces [1], Such proteins are anchored by a PI moiety in which the 6 position of inositol is glycosidically linked to glucosamine, which in turn is bonded to a polymannan backbone (Fig. 3-10). The polysaccharide chain is joined to the carboxyl terminal of the anchored protein via amide linkage to ethanolamine phosphate. The presence of a free NH2 group in the glucosamine residue makes the structure labile to nitrous acid. Bacterial PI-PLC hydrolyzes the bond between DAG and phosphati-dylinositols, releasing the water-soluble protein polysac charide-inositol phosphate moiety. These proteins are tethered by glycosylphosphatidylinositol (GPI) anchors. 

Problem 22.36 Cellobiose, isolated from the polysaccharide cellulose, has the same chemistry as maltose except that it is hydrolyzed by emulsin. Give the structure of this disaccharide. ... 

PrObtom 22.42 The polysaccharide amylose, the water-soluble component of starch, is hydrolyzed to ( + )-maltose and D-(-t-)-glucose, Methylated and hydrolyzed, amylose gives mainly 2,3,6-tri-O-methyl-D-glucopyranose. Deduce the structure of amylose. 4... 

Structural Analysis of a Polysaccharide A polysaccharide of unknown structure was isolated, subjected to exhaustive methylation, and hydrolyzed. Analysis of the products revealed three methylated sugars in the ratio 20 1 1. The sugars were 2,3,4-tri-O-methyl-D-glucose 2,4-di-O-methyl-D-glucose and 2,3,4,6-tetra-O-methyl-D-glucose. What is the structure of the polysaccharide ... 

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