Disaccharides are carbohydrates composed of two monosaccharide units linked together by a glycosidic bond formed via a condensation (dehydration) reaction. They have the general chemical formula C12H22O11. The glycosidic bond is a covalent linkage between the hydroxyl groups of the two monosaccharides, which may differ in position and configuration (α or β), leading to various types of disaccharides with distinct properties.
Common Types of Disaccharides
- Sucrose: composed of glucose and fructose, connected via an α-1,2-glycosidic bond. It is a non-reducing sugar because both anomeric carbons are involved in the bond.
- Lactose: composed of glucose and galactose, linked by a β-1,4-glycosidic bond.
- Maltose: composed of two glucose units linked by an α-1,4-glycosidic bond.
Disaccharides are soluble in water and serve as an important energy source in organisms. Upon hydrolysis, disaccharides yield two monosaccharides which can then enter metabolic pathways. The formation and cleavage of disaccharides involve enzymatic processes crucial to digestion and metabolism.
