InterPro: IPR004139 Glycosyl transferase, family 13

The biosynthesis of disaccharides, oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases. These enzymes catalyse the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. A classification of glycosyltransferases using nucleotide diphospho-sugar, nucleotide monophospho-sugar and sugar phosphates (EC:2.4.1.-) and related proteins into distinct sequence based families has been described [1]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site [2]. The same three-dimensional fold is expected to occur within each of the families. Because 3-D structures are better conserved than sequences, several of the families defined on the basis of sequence similarities may have similar 3-D structures and therefore form 'clans'.

Alpha-1,3-mannosyl-glycoprotein beta-1,2-N-acetylglucosaminyltransferase (GNT-I, GLCNAC-T I) EC:2.4.1.101 transfers N-acetyl-D-glucosamine from UDP to high-mannose glycoprotein N-oligosaccharide. This is an essential step in the synthesis of complex or hybrid-type N-linked oligosaccharides. The enzyme is an integral membrane protein localized to the Golgi apparatus, and is probably distributed in all tissues. The catalytic domain is located at the C terminus [3]. These proteins are members of the glycosyl transferase family 13 (GH13)