Enzymatic synthesis of some O-beta-D-digalactosyl glycopeptides, using beta-D-galactosidase.
Disaccharide-peptide conjugates were obtained in yields of 30-50% from o-nitrophenyl beta-D-galactopyranoside by employing beta-D-galactosidase from E. coli as catalyst. Two series of beta-D-galactosyldipeptides were examined as galactosyl acceptors. They both contain an L-serine residue beta-linked to the anomeric carbon of galactose. In the first series, serine is in the N-terminal position of the dipeptide; in the second series, serine is in the C-terminal position. The second amino acid is L-alanine or glycine. Some of our substrates gave a high yield of beta-(1-->3)-digalactosyldipeptide derivatives and all gave very little of the beta-(1-->6) regioisomer. The conditions and the limitations of the transgalactosylation reaction are discussed.
Bay
S
S
Départment de Biochimie et Génétique Moléculaire, Institut Pasteur, U.A. CNRS 487, Paris 15, France.
Namane
A
A
Cantacuzene
D
D
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis*; D004926:Escherichia coli / Q000201:enzymology; D005690:Galactose; D006020:Glycopeptides / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009904:Optical Rotation; D001616:beta-Galactosidase
D004187:Disaccharides; D006020:Glycopeptides; D007202:Indicators and Reagents; D001616:beta-Galactosidase; D005690:Galactose