A convenient synthesis of β-D-galactosyl disaccharide derivatives using the β-D-galactosidase from Bacillus circulans

Article abstract of DOI:10.1016/0008-6215(83)85010-1

β-D-Gal-(1 → 4)-β-D-GlcNAc-OC₆H₄NO₂-p (p-nitrophenyl N-acetyl-β-lactosaminide) and β-D-Gal-(1 → 6)-β-D-GlcNAc-OC₆H₄NO₂-p (p-nitrophenyl N-acetyl-β-isolactosaminide) were regioselectively synthesized from lactose and p-nitrophenyl 2-acetamido-2-deoxy-glucopyranoside, employing transglycosylation by the β-D-galactosidase from Bacillus circulans and by controlling the concentration of organic solvent in the reaction system. The (1 → 4)-linked disaccharide was formed exclusively when the concentration of organic solvent was high, whereas the (1 → 6)-linked isomer was produced with a low concentration. Further utilization of the transglycosylation by the enzyme led to the regioselective formation of β-D-Gal-(1 → 4)-D-GalNAc and β-D-Gal-(1 → 4)-β-D-GalNAc-OC₆H₄NO₂-p. With the enzyme, β-D-galactosyl transfer occurred preferentially at the O-4 position of GlcNAc and GalNAc, regardless of the configuration of the hydroxyl group. β-D-Gal-(1→4)-b-D-GlcNAc-OC₆H₄NO₂-p (p-nitrophenyl N-acetyl-β-lactosaminide) and β-D-Gal-(1→6)-β-D-GlcNAc-OC₆H₄NO₂-p (p-nitrophenyl N-acetyl-β-isolactosaminde) were regioselectively synthesized from lactose and p-nitrophenyl 2-acetamido-2-deoxy-glucopyranoside, employing transglycosylation by the b-D-galactosidas from Bacillus circulans and by controlling the concentration of organic solvent in the reaction system. The (1→4) linked disaccharide was formed exclusively when the concentration of organic solvent was high, whereas the (1→6)-linked isomer was produced with a low concentration. Further utilization of the transglycosylation by the enzyme led to the regioselective formation of β-D-Gal-(1→4)-D-GalNAc and β-D-Gal-(1→4)-β-D-GalNAc-OC₆H₄NO₂-p. With the enzyme, β-D-galactosyl transfer occurred preferentially at the O-4 position of GlcNAc, regardless of the configuration of the hydroxyl group.