Earle M A, Manku S, Hultin P G, Li H, Palcic M M
Department of Chemistry, University of Manitoba, Winnipeg, Canada.
Carbohydr Res. 1997 Jun 11;301(1-2):1-4. doi: 10.1016/s0008-6215(97)00085-2.
A trimeric beta-lactosyl cluster based on 2-nitro-2-(hydroxymethyl)propane-1,3-diol was prepared using the trichloroacetimidate method. Kinetic studies showed that this cluster was an effective acceptor for rat-liver alpha-(2-->3)-sialyltransferase. Its KM was comparable to those for monomeric lactose and N-acetyllactosamine acceptors, and its Vmax was 1% of that measured for the LacNAc acceptor. Preparative-scale sialylation using this enzyme afforded a trimeric cluster of the ganglioside GM3 oligosaccharide in good yield. The NMR spectra of the trimeric GM3 analogue suggest that the oligosaccharide conformation is not significantly perturbed by this level of clustering.
采用三氯乙酰亚胺酯法制备了基于2-硝基-2-(羟甲基)丙烷-1,3-二醇的三聚体β-乳糖基簇。动力学研究表明，该簇是大鼠肝脏α-(2→3)-唾液酸转移酶的有效受体。其米氏常数与单体乳糖和N-乙酰乳糖胺受体的米氏常数相当，其最大反应速度是LacNAc受体的1%。使用该酶进行制备规模的唾液酸化反应，以良好的产率得到了神经节苷脂GM3寡糖的三聚体簇。三聚体GM3类似物的核磁共振谱表明，这种程度的簇化对寡糖构象没有明显干扰。
