Oligosaccharides unsaturated, synthesis

The synthesis of an interesting glycosyl bromide derivative (107) has been described it can be used for the synthesis, by way of 108, of unsaturated oligosaccharides that have been obtained, by enzyme-catalyzed /8-elimination, from glycosaminoglycans, pectin, or alginic acid. 

An enzyme that hydrolyses dermatan sulphate, but neither chondroitin 4-sulphate nor chondroitin 6-sulphate, has been isolated from Flavobacterium heparinum grown in the presence of glycosaminoglycans. Chondroitin and dermatan sulphates and disaccharides obtained from them induced the synthesis of this enzyme, which was separated from a chondroitin sulphate lyase AC. The enzyme acted on dermatan sulphate to give an unsaturated, sulphated disaccharide and higher oligosaccharides. 

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