α-Galactosidase

α-Galactosidase ( EC 3.2.1.22, α-GAL, α-GAL A; systematic name α-D-galactoside galactohydrolase) is a glycoside hydrolase enzyme that catalyses the following reaction:[1] It catalyzes many catabolic processes, including cleavage of glycoproteins, glycolipids, and polysaccharides.

It predominantly hydrolyzes ceramide trihexoside, and it can catalyze the hydrolysis of melibiose into galactose and glucose.

[citation needed] α-Galactosidase from Aspergillus niger is the active ingredient in Beano, a dietary supplement for bloating and flatulence.

[6][7] Recombinant α-galactosidase made by baker's yeast is approved in Europe as a feed additive intended to make poultry food more digestible.

[8] This article incorporates text from the United States National Library of Medicine, which is in the public domain.

A double displacement reaction mechanism of α-GAL's catalytic action. The ligand (black) when bound in the active site of the enzyme (blue). The two key amino acid residues in the active site are Asp-170 and Asp-231. First, Asp-170 performs a nucleophilic attack on the glycosidic bond to release the terminal α-galactose molecule from the ligand. Then, Asp-231 serves as an acid to remove a proton from water, making it more nucleophilic to attack the galactose-Asp complex and release α-galactose from the active site. [ 3 ] [ 4 ] [ 5 ]