Galactose (EP)
Galactose, also known as milk sugar, is a monosaccharide, meaning it is a simple sugar that cannot be hydrolyzed into smaller units. It is a hexose, which signifies that it contains six carbon atoms. Its chemical formula is C6H12O6, the same as glucose and fructose, but it has a different structural arrangement of atoms, giving it distinct properties.
Galactose exists in both open-chain and cyclic forms. In solution, it predominantly exists as a cyclic hemiacetal, with two isomers: α-galactose and β-galactose, determined by the orientation of the hydroxyl group on the first carbon atom.
Galactose is less sweet than glucose and fructose. It is a component of lactose, a disaccharide found in milk, which is formed when galactose and glucose are linked by a β-1,4-glycosidic bond.
In humans, galactose is obtained primarily through the digestion of lactose. It is then converted into glucose through a series of enzymatic reactions in the liver, known as galactose metabolism or the Leloir pathway. This glucose can then be used for energy production.
Galactosemia is a genetic metabolic disorder in which the body is unable to properly metabolize galactose. This can lead to a buildup of galactose in the blood, causing serious health problems, particularly in infants. Treatment for galactosemia typically involves eliminating galactose from the diet.
Galactose is also found in some plants and fruits, and it is a component of some complex carbohydrates and glycoproteins. It plays a role in various biological processes, including cell signaling and cell adhesion.