白藜芦醇葡萄糖苷的生物合成

为研究淀粉蔗糖酶催化白藜芦醇的性质,从中度嗜热菌Deinococcus geothermalis克隆淀粉蔗糖酶基因dgas并在大肠杆菌中诱导表达,纯化淀粉蔗糖酶DGAS。经SDS-PAGE检测DGAS的分子量为73.0 kDa。以蔗糖为葡萄糖基供体,白藜芦醇为受体,DGAS催化合成2个白藜芦醇葡萄糖苷。大规模培养表达制备淀粉蔗糖酶DGAS,催化白藜芦醇进行糖基化反应,经柱层析分离纯化得到2个化合物1和2。经NMR波谱解析化合物1和2分别鉴定为白藜芦醇-4’-O-α-D-吡喃葡萄糖苷和白藜芦醇-4’-O-α-D-吡喃葡萄糖基-(1→4)-O-α-D-吡喃葡萄糖苷。在室温条件下,白藜芦醇-4’-O-α-D-吡喃葡萄糖苷在水中溶解度为2.26 mg/mL。

Resveratrol Glucoside Biosynthesis

To study the glycosylation of resveratrol,an amylosucrase from Deinococcus geothermali(DGAS)was cloned and expressed in Escherichia coli BL21(DE3).The molecular weight of DGAS was 73.0 kDa as shown by SDSPAGE.Using sucrose as the glucoside donor and resveratrol as the acceptor,DGAS synthesized two resveratrol glucosides.DGAS was prepared and used to catalyze resveratrol glycosylation in large scale.The reaction products were subjected to column chromatography.Two resveratrol glucosides 1 and 2 were purified.Their structure were determined to be resveratrol-4’-O-α-D-glucopyranoside(1)and resveratrol-4’-O-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranoside(2)by NMR,respectively.The solubility of resveratrol-4’-O-α-D-glucopyranoside in water was 2.26 mg/mL at room temperature.