Galactosidases

Galactosidases are enzymes (glycoside hydrolases) that catalyze the hydrolysis of galactosides into monosaccharides.

The galactosidases are categorized as either alpha or beta, according to the category of glycoside they hydrolyze. The enzyme corresponding to an alpha-galactoside is called alpha-galactosidase; it catalyzes the hydrolysis of substrates that contain α-galactosidic residues, such as glycosphingolipids or glycoproteins. On the other hand, the enzyme corresponding to beta-galactosides is called beta-galactosidase; it breaks down the disaccharide lactose for instance, 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.

B-galactosidase forms the basis of lac z operon in bacteria which can be used to control gene expression.