(p-nitrophenyl N-acetyl-beta-isolactosaminide) were regioselectively synthesized from lactose and p-nitrophenyl 2-acetamido-2-deoxy-glucopyranoside, employing transglycosylation by the beta-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
β-D-Gal-(1-> 4)-β-D-GlcNAc-OC6H4NO2-p(对
硝基苯基N-乙酰基-
β-乳糖苷)和β-D-Gal-(1-> 6)- β-D-GlcNAc-OC6H4NO2-p(对
硝基苯基N-乙酰基-β-异
乳糖胺)是通过
乳糖和对
硝基苯基2-乙酰
氨基-2-脱氧
葡萄糖吡喃糖苷进行区域选择性合成的,其中β-
D-半乳糖苷酶通过芽孢杆菌回旋菌并通过控制反应体系中有机溶剂的浓度。当有机溶剂的浓度较高时,仅形成(1→4)连接的二糖,而低浓度时生成(1→6)连接的异构体。酶进一步利用转糖基化作用导致β-D-Gal-(1→4)-D-GalNAc和β-D-Gal-(1→4)-β-D-的区域选择性形成GalNAc-OC6H4NO2-p。用酵素