Glycosidic bond of sugar unit

Polysaccharides chains are generally formed by a repeated sequence of monomers or oligomers. Few monosaccharides exist in the free state. They generally occur linked by glycosidic bond to one another or to an aglycones.

The term ‘glycosidic bond’ is used for the bond between the anomeric C-atom and the glycosidic O (N-, S,) atom.

While the term ‘glycosidic linkage is used to define a set of all bonds that connects to monosaccharide rings.

It is a bond that links two sugar units together; it is formed between the free carbonyl group of one sugar and a hydroxyl group of another sugar; the orientation (α or β) and position (eg. 1,4) of the link must be specified. The structure of a di-, oligo- or polysaccharide sugar is based on the bonding of two monosaccharides.

In the case of a disaccharide, two monosaccharides are joined with loss of one molecule of water. This joining occurs between two –OH groups, one of each monosaccharide.
Glycosidic bond of sugar unit