Synthesis of Oligosaccharides Related to Bacterial Cell Wall Polysacchairdas Steroidal Glycosides and Blood Group Antigens

Abstract

from the Greek word saccharon meaning sugar.3 Carbohydrates that cannot be hydrolyzed into simpler compounds are called “monosaccharides” such as glucose, fructose etc. and a carbohydrate that can be hydrolyzed to two monosaccharides is called a disaccharide. e.g., sucrose, maltose, lactose, melibiose, cellobiose etc. while those composed of many monosaccharide units are called polysaccharides. Carbohydrates with an aldehydic group are known as “aldoses” and those with a ketonic functionality are “ketoses”. Depending upon the number of carbon atoms it contains, the monosaccharide is termed as tetrose, pentose, hexose and so on. Polysaccharides can also be classified4-6 into homopolysaccharide and heteropolysaccharide depending on the monosaccharide units present. The carbohydrates those containing only one type of monosaccharide units are called homopolysaccharides e.g. glucans, mannans, galactans, arabinans etc. whereas heteropolysaccharides contain two or more different monosaccharide units, e.g. glucomannans, galactomannans, arabinogalactans etc. Depending upon their functional property, polysaccharides can be divided into two parts. One is fibrous polysaccharide, e.g. cellulose in higher plants and some algae, chitin in yeast and fungi. The other one is the polysaccharide having matrix forming property and is characterized by their gel forming characteristics which confer flexibility on the structural assembly. Arabinoxylans, galactomannans of plant origin represent this group.