OGlykosidbindung

An O-glycosidic bond is a type of covalent bond that links a carbohydrate molecule to another group via an oxygen atom. This other group can be another carbohydrate, forming a disaccharide or polysaccharide, or it can be a non-carbohydrate moiety, such as a lipid (forming a glycolipid) or a protein (forming a glycoprotein). In this linkage, the anomeric carbon of the carbohydrate, which is the carbon atom derived from the hemiacetal or hemiketal group of the open-chain form of the sugar, is bonded to an oxygen atom. This oxygen atom is typically part of a hydroxyl group on the other molecule.

The formation of an O-glycosidic bond involves a dehydration reaction, where a molecule of water is removed. This process is catalyzed by enzymes called glycosyltransferases in biological systems. The breakdown of O-glycosidic bonds, conversely, occurs through hydrolysis, where a molecule of water is added to break the bond. The stability and properties of the resulting glycoside are determined by the nature of the carbohydrate and the aglycone (the non-carbohydrate part). O-glycosidic bonds are fundamental to the structure and function of many biological molecules, including structural polysaccharides like cellulose and chitin, energy storage molecules like starch and glycogen, and a vast array of signaling molecules and components of cell membranes.