Degradation of polysaccharides

Early in the 1950s, Stacey was successful in his negotiations to have a 60Co source of y-rays installed in his laboratory. Then, in collaboration with Barker and Bourne, a series of investigations of the effects of y-radiation on saccharides was started. Both polymer formation from simple sugars and the degradation of polysaccharides were studied. 

Chemical stabilizers have been used to reduce the rate of oxygen-promoted degradation of polysaccharides at T>225°F. Methanol and sodium thiosulfate are the most commonly used (86). Sodium dithio-carbamate, alkanolamines, and thiol derivatives of imidazolines, thiazolines, and other heterocyclic compounds have also been tested for this application. Calcined dolomite (B7) and Cu(l) and Cu(ll) salts (88) have been reported to increase the thermal stability of HEC. 

Viral enzyme for degradation of polysaccharides trimer of /3-solenoids with L-type cross section and a small left-handed twist... 

Swainsonine (1) is of great biochemical interest since it is a potent and specific inhibitor of both lysosomal a-mannosidase and mannosidase II, which are involved in the cellular degradation of polysaccharides and in the processing of asparagine-linked glycoproteins, respectively [1]. 

While the stomach acid in humans and most animals can degrade polysaccharides to the energy-giving monomeric units, this is not efficient unless a specific enzyme, which is normally present in the gut, allows the ready and rapid degradation of polysaccharide. Since these enzymes are somewhat specific, their ability to degrade is polysaccharide-specific. 

Aldoses and aldosides, cyclic acetals of, 20, 219-302 Alkaline degradation, of polysaccharides, 13, 289-329 Altrose,... 

Degradation of Polysaccharides Containing Uronic Acid Residues.. . . 214... 

The method most commonly used to determine sequences is graded hydrolysis with acid, followed by fractionation and identification of the resulting oligosaccharides. The information obtained by this method is qualitative only, and it may be difficult to assess the structural significance of oligosaccharides formed in low yield. There is, therefore, a need for more selective or, preferably, specific methods for the degradation of polysaccharides. 

Only a few methods for the specific degradation of polysaccharides were known when an earlier article on structural polysaccharide chemistry appeared in this Series.3 The Smith degradation,4 which has become the most frequently used, had only just been introduced. Since then, a number of specific degradation techniques have been developed. In addition, there have also been some modifications and improvements to existing methods. In this article, chemical methods for specific or selective degradation of polysaccharides, and their applications in structural analysis, will be discussed. Enzymic methods, which may be of considerable value, have already been treated in this Series.5... 

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