<p>O-Glycosyl hydrolases <db_xref db="EC" dbkey="3.2.1."/> are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [<cite idref="PUB00004870"/>, <cite idref="PUB00005266"/>]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site.</p><p> Families 27 (<db_xref db="CAZY" dbkey="GH27"/>) and 36 (<db_xref db="CAZY" dbkey="GH36"/>) encompasses alpha-galactosidases and alpha-N-acetylgalactosaminidases in which two conserved Asp residues may be involved in the catalytic mechanism. Alpha-galactosidase (melibiase) catalyses the hydrolysis of melibiose into galactose and glucose [<cite idref="PUB00005652"/>]. In man, deficiency in the enzyme results in Fabry's disease (X-linked sphingolipidosis). Alpha-N-acetylgalactosaminidase catalyses the hydrolysis of terminal non-reducing N-acetyl-D-galactosamine residues in N-acetyl-alpha-D-galactosaminides [<cite idref="PUB00002595"/>]. Deficiency in this enzyme results in Schindler and Kanzaki diseases.</p><p> This group identifies specifically melibiase.</p> Glycoside hydrolase, melibiase