α-环糊精葡萄糖基转移酶催化合成α-熊果苷

α-Arbutin synthesis by α-cyclodextrin glycosyltransferase

以对苯二酚和麦芽糊精为底物,通过α-环糊精葡萄糖基转移酶和淀粉葡萄糖苷酶的两步酶法反应体系催化合成α-熊果苷。优化后的催化条件：以葡萄糖当量（DE）值为8%~10%的麦芽糊精作为供体底物,麦芽糊精60g/L,对苯二酚150 mmol/L,缓冲液p H 6.0,在40℃下反应24 h。在此反应条件下,α-熊果苷的产量为3.17 g/L,对苯二酚转化率为7.77%。通过萃取法对α-熊果苷进行了初步分离,再经高效液相色谱-电喷雾串联质谱技术进行了结构测定,确定产物为α-熊果苷。

α-Arbutin was synthesized by α-cyclodextrin glycosyltransferase and amyloglucosidase,with hydroquinone and maltodextrin as substrates. The reactions were carried out in an aqueous system containing hydroquinone as acceptor and maltodextrin as donor substrate molecules. A two-step enzymatic reaction system comprising of α-cyclodextrin glycosyltransferase and amyloglucosidase helped to attain a high yield of α-arbutin. The reaction conditions were optimized with single factor experiments. The optimal conditions for catalysis were obtained： hydrolysis of maltodextrin dextrose equivalent（ DE） value between 8% and 10% as donor substrate,hydroquinone 150 mmol / L,maltodextrin 60 g / L,buffer p H6. 0,incubation at 40 ℃ for 24 h. The yield of α-arbutin was 3. 17 g / L under the optimized reaction conditions,the yield of hydroquinone was 7. 77%. α-arbutin was purified by organic solvent extraction and the major glycoside product was identified as α-arbutin on the basis of high performance liquid chromatography-electrospray tandem mass spectrometry.