THE USE OF IMMOBILIZED GLYCOSYLTRANSFERASES IN THE SYNTHESIS OF SIALYLOLIGOSACCHARIDES

The CMP-sialic acids, cytidine 5′-(5-acetamido-3,5-dideoxy-β-d-glycero-d-galacto-2-nonulopyr anosylonic acid monophosphate) (1) and cytidine 5′-(5-acetamido-9-O-acetyl-3,5-dideoxy-β-d-glycero-d-galacto- 2-nonulopyranosylonic acid monophosphate (2) were prepared from CMP, phosphoenolpyruvate, N-acetylneuraminic acid or its 9-acetate, and a catalytic amount of ATP in the presence of immobilised pyruvate kinase, nucleoside monophosphate kinase, inorganic pyrophosphatase, and CMP-sialic acid synthetase. CMP-NeuAc (1) was used as a donor of N-acetylneuraminic acid in the reaction catalysed by immobilised porcine liver β-d-Galp-(1→4)-α-d-GlcpNAc-(2→6)-sialytransferase. α-d-Neup5Ac-(2→6)-β- d-Galp-(1→4)-β-d-GlcpNAc-(1→2)-α-d-Man-OMe (5) was obtained on a 0.1-mmol scale by enzymic sialylation of β-d-Galp-(1→4)-β-d-GlcpNAc-(1→2)-α-d-Man-OME 4), prepared by enzymic galactosylation of β-d-GlcpNAc-(1→2)-α-d-Man-OMe (3). Likewise, using 2, α-d-Neup-5,9Ac2-(2→6)-β-d-Galp- (1→4)-d-GlcpNAc (7) was obtained from N-acetyl-lactosamine (6). © 1990.