Hedbys L, Johansson E, Mosbach K, Larsson P O, Gunnarsson A, Svensson S, Lönn H
Department of Pure and Applied Biochemistry, University of Lund, Sweden.
Glycoconj J. 1989;6(2):161-8. doi: 10.1007/BF01050645.
Gal beta 1-3GlcNAc (1) and Gal beta 1-3GlcNAc beta-SEt (2) were synthesized on a 100 mg scale by the transgalactosylation reaction of bovine testes beta-galactosidase with lactose as donor and N-acetylglucosamine and GlcNAc beta-SEt as acceptors. In both cases the product mixtures contained unwanted isomers and were treated with beta-galactosidase from Escherichia coli which has a different specificity, under conditions favouring hydrolysis, yielding besides the desired products, monosaccharides and traces of trisaccharides. The products were purified to greater than 95% by gel filtration, with a final yield of 12% of 1 and 17% of 2, based on added acceptor. In a separate experiment Gal beta 1-6GlcNAc beta-SEt (3) was synthesized by the transglycosylation reaction using beta-galactosidase from Escherichia coli. No other isomers were detected. Compound 3 was purified by HPLC.
以乳糖为供体，N-乙酰葡糖胺和GlcNAcβ-SEt为受体，通过牛睾丸β-半乳糖苷酶的转半乳糖基化反应，以100mg规模合成了Galβ1-3GlcNAc（1）和Galβ1-3GlcNAcβ-SEt（2）。在这两种情况下，产物混合物都含有不需要的异构体，并在有利于水解的条件下用具有不同特异性的大肠杆菌β-半乳糖苷酶处理，除了所需产物外，还产生了单糖和痕量三糖。通过凝胶过滤将产物纯化至大于95%，基于添加的受体，1的最终产率为12%，2的最终产率为17%。在一个单独的实验中，使用大肠杆菌的β-半乳糖苷酶通过转糖基化反应合成了Galβ1-6GlcNAcβ-SEt（3）。未检测到其他异构体。化合物3通过HPLC纯化。
