Galactosidases are enzymes (glycoside hydrolases) that catalyze the hydrolysis of galactosides into monosaccharides.
Galactosides can be classified as either alpha or beta. If the galactoside is classified as an alpha-galactoside, the enzyme is called alpha-galactosidase, and is responsible for catalyzing the hydrolysis of substrates that contain α-galactosidic residues, such as glycosphingolipids or glycoproteins. On the other hand, if it is a beta-galactoside, it is called beta-galactosidase, and is responsible for breaking down the disaccharide lactose into its monosaccharide components, glucose and galactose. Both varieties of galactosidase are categorized under the EC number 3.2.1.
Two recombinant forms of alpha-galactosidase are called agalsidase alfa (INN) and agalsidase beta (INN). Lack of alpha-galactosidase activity in leukocytes has been linked to Fabry Disease.
Galactosidases have a variety of uses, including the production of prebiotics, the biosynthesis of transgalactosylated products, and the removal of lactose.