title: The use of an immobilised cyclic multi-enzyme system to synthesise branched penta- and hexa-saccharides associated with blood-group I epitopes.
abstract: The branched hexasaccharide beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)- [beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----6)]-beta-D-Galp-(1----4)-beta -D- GlcOMe (1) was obtained on a 0.1-mmol scale by enzymic bigalactosylation of the tetrasaccharide beta-D-GlcpNAc-(1----3)-[beta-D-GlcpNAc-(1----6)]-beta-D-Galp-(1----4)-b eta- D-GlcOMe by the use of an immobilised multi-enzyme system which regenerated UDP-alpha-D-galactose in situ. The formation of 1 proceeded in two steps. An intermediate compound was identified on the basis of 1H- and 13C-n.m.r. data as the pentasaccharide beta-D-GlcpNAc-(1----3)-[beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----6)]-b eta- D-Galp-(1----4)-beta-D-GlcOMe.
mesh_terms: D001789:Blood Group Antigens; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005700:Galactosyltransferases / Q000378:metabolism; D007048:I Blood-Group System; D043564:Inorganic Pyrophosphatase; D009682:Magnetic Resonance Spectroscopy; D009844:Oligosaccharides / Q000138:chemical synthesis*; D011755:Pyrophosphatases / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D014534:UDPglucose 4-Epimerase / Q000378:metabolism; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase / Q000378:metabolism
chemical_list: D001789:Blood Group Antigens; D004800:Enzymes, Immobilized; D007048:I Blood-Group System; D009844:Oligosaccharides; D005700:Galactosyltransferases; D011770:Pyruvate Kinase; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase; D014534:UDPglucose 4-Epimerase