acceptor, beta-D-Galp-(1----3)-beta-D-GlcpNAc-OMe was formed in only slightly excess over teh analogous beta-(1----4)-linked glycoside. The use of beta-D-galactosidase and beta-D-galactoside 3-alpha-sialyltransferase in sequence provided a convenient route to the trisaccharide glycosides alpha-D-Neup5Ac-(2----3)-beta-D-Galp-(1----3)-alpha-D-GalpNAc-OEt, alpha-D-Neup5Ac-(2----3)-beta-D-Galp-(1----3)-beta-D-GalpNAc-OE
通过使用糖苷酶作为
催化剂,从适当的供体和受体糖苷中获得以下二糖苷的收率为10%至35%:α-D-Galp-(1 ---- 3)-alpha-D-GalpNAc-OEt(alpha -
D-半乳糖苷酶),beta-D-Galp-(1 ---- 3)-alpha-D-GalpNAc-OEt和beta-D-Galp-(1 ---- 3)-beta-D-GalpNAc- OEtBr(β-
D-半乳糖苷酶),β-D-GlcpNAc-(1 ---- 6)-β-D-Galp-OMe和β-D-GlcpNAc-(1 ---- 6)-alpha-D -Manp-OMe(β-
N-乙酰
氨基
葡糖苷酶)。使用β-D-GlcpNAc-OEtSiMe3作为受体时,β-
D-半乳糖苷酶几乎完全提供了β-D-Galp-(1 ---- 3)-β-D-GlcpNAc-OEtSiMe3,而使用β-D- GlcpNAc-OMe作为受体,形成的β-D-Galp-(1