Genre: Information/Explanation

The biosynthesis of disaccharides , oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases . These are enzymes that 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 ( 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 ' . Glycosyltransferase family 28 GT_28 comprises enzymes with a number of known activities ; 1 , 2-diacylglycerol 3-beta-galactosyltransferase ( 2 . 4 . 1 . 46 ) ; 1 , 2-diacylglycerol 3-beta-glucosyltransferase ( 2 . 4 . 1 . 157 ) ; beta-N-acetylglucosamine transferase ( 2 . 4 . 1 . - ) . Structural analysis suggests the C-terminal domain contains the UDP-GlcNAc binding site .