Polysaccharides amino sugar

Biologically active components of the organic soil fraction include polysaccharides, amino sugars, nucleotides, and organic sulfur and phosphorus compounds. Humus, a water-insoluble material that biodegrades very slowly, makes up (he bulk of soil organic matter. The organic compounds in soil are summarized in Table 18.1. 

In tandem with his studies of polysaccharides, Stacey had a research group investigating the chemistry of the unusual sugars found as components of carbohydrate macromolecules. In this context, derivatives of simple sugars, di- and trisaccharides, uronic acids, deoxy sugars, amino sugars, sugar sulfates, and phosphates were studied. 

L-Fucosamine was found as a constituent of Pneumococcus Type V capsular polysaccharide and as a constituent of the mucopolysaccharides (glycosamino-glycans) of certain enteric bacteria A new synthesis was devised to make the amino sugar more available. 

The generic term monosaccharide (as opposed to oligosaccharide or polysaccharide) denotes a single unit, without glycosidic connection to other such units. It includes aldoses, dialdoses, aldoketoses, ketoses and diketoses, as well as deoxy sugars and amino sugars, and their derivatives, provided that the parent compound has a (potential) carbonyl gTOup. 

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. 

A polysaccharide composed entirely of amino sugar residues is named by appropriate modification of the systematic amino sugar name. 

Pneumococcus, polysaccharides from, 6-7 Poly(a-L-guluronic acid), 353, 355-356,415 Poly(P-D-mannuronic acid), 353-354,414 Polysaccharides, 311 -439 amino sugar derivatives, 166 chemical repeating units, 321, 324-325... 

Polysaccharides of Corynebacterium diphtheriae yield D-galactose, pentoses and amino sugars on hydrolysis.79 D-Glucose and D-mannose are major hydrolytic products of the polysaccharide of Clostridium perfringens.80 Complete hydrolysis81 of the polysaccharide of the anthrax bacillus yielded acetyl-D-glucosamine and D-galactose. 

The purification of a pneumococcal polysaccharide may be difficult, and the polysaccharide material is sometimes contaminated by a cell-wall component known as the C-substance. The methods for structural analysis of polysaccharides (which, like several of the pneumococcal polysaccharides, contain amino sugar and uronic acid... 

The difficulties inherent in obtaining correct sugar analyses for a polysaccharide containing three different amino sugars are obvious. It therefore seems possible that S4 is composed of tetrasaccharide repeating-units, containing one residue each of the four different sugar components. 

Figure 22.11. Cellulose is a structural and rather chemically inert component of terrestrial plants. Alginic acid is synthesized by marine algae and has medicinal properties. Some polysaccharides contain nitrogen in the form of amino sugars. The primary example of this is chitin, which composes the exoskeletons of Crustacea. An amino sugar contains an amine in place of a hydroxyl group. In other polysaccharides, sugars combine with lipids and proteins. These form glycoUpids and glycoproteins, respectively.

---