The glycosyltransferases are a family of some 250-300 different intracellular, mebrane-bound enzymes that participate in the coordinate biosynthesis of the glycostructures of polypeptides, including glycoproteins, proteoglycans and glycolipids. They are classified into groups based on their nucleotide monosaccharide donor specificity. For example, the galactosyltransferases use UDP-galactose as the activated monosaccharide donor whereas the sialytransferases use CMP-sialic acid and the fucosyltransferases use GDP-fucose. (Hueller, US14348822)

Examples of Glycosyltransferases

Examples of glycosyltransferases include galacosyltransferases, fucosyltransferases, glucosyltransferase, N-acetylgalactosiminyltransferases, N-acetylglucosaminyltransferases, glucuronyltransferases, sialyltransferanses, mannosyltransferases, and oligosaccharyltransferases. 

Prokaryotic glycosyltransferases include enzymes involved in synthesis of lipooligosaccharides (LOS), which are produced by many gram negative bacteria. The LOS typically have terminal glycan sequences that mimic glycoconjugates found on the surface of human epithelial cells or in host secretions. 

Large scale enzymatic synthesis of oligosaccharides depends on the availability of sufficient quantities of the required glycosyltransfereases. Glycosyltransferases can be used as regio- and steroselective catalysts for the in vitro synthesis of oligosaccharides. However, production of glycosyltransferases in sufficient quantities for use in preparing oligosaccharide structures has been problematic. WO98/54331 discloses modified nucleic acids which encode glycosyltransferases having enhanzed hield .