Kida H, Akao T, Meselhy M R, Hattori M
Department of Cell-Resources Engineering, Research Institute for Wakan-Yaku (Traditional Sino-Japanese Medicines), Sugitani, Toyama, Japan.
Biol Pharm Bull. 1997 Dec;20(12):1274-8. doi: 10.1248/bpb.20.1274.
From a human intestinal bacterium, Eubacterium sp. A-44, which is capable of hydrolyzing saikosaponins to saikogenins, two glycosidases, beta-D-glucosidase and a novel type of beta-D-fucosidase, were isolated and characterized as saikosaponin-hydrolyzing beta-D-glucosidase and prosaikogenin-hydrolyzing beta-D-fucosidase. Relative to the hydrolyzing activities toward saikosaponins a, b1 and b2, the beta-D-glucosidase showed lower ability to hydrolyze saikosaponin d, but no ability to hydrolyze saikosaponin c or prosaikogenins. By Sephacryl S-300 column chromatography, the molecular weight of prosaikogenin-hydrolyzing beta-D-fucosidase was estimated to be about 130 kDa. The beta-D-fucosidase could hydrolyze prosaikogenins A and F, but not prosaikogenins D and G or saikosaponins. Relative to p-nitrophenyl beta-D-fucoside-hydrolyzing activity, this enzyme had 32.0% and 22.2% of its hydrolyzing ability toward p-nitrophenyl beta-D-glucoside and p-nitrophenyl beta-D-galactoside, respectively. p-Nitrophenyl beta-D-fucoside-hydrolyzing activity was inhibited by D-fucose, and was weakly inhibited by D-glucose, D-glucono delta-lactone, D-galactose and D-galactono delta-lactone. By combining these two glycosidases, saikosaponins a and b1 were converted to their saikogenins via the corresponding prosaikogenins.
从能够将柴胡皂苷水解为柴胡皂苷元的人肠道细菌真杆菌属A-44中，分离出两种糖苷酶，即β-D-葡萄糖苷酶和一种新型的β-D-岩藻糖苷酶，并将它们分别鉴定为水解柴胡皂苷的β-D-葡萄糖苷酶和水解前柴胡皂苷元的β-D-岩藻糖苷酶。相对于对柴胡皂苷a、b1和b2的水解活性，β-D-葡萄糖苷酶对柴胡皂苷d的水解能力较低，但对柴胡皂苷c或前柴胡皂苷元没有水解能力。通过Sephacryl S-300柱色谱法，估计水解前柴胡皂苷元的β-D-岩藻糖苷酶的分子量约为130 kDa。β-D-岩藻糖苷酶可以水解前柴胡皂苷元A和F，但不能水解前柴胡皂苷元D和G或柴胡皂苷。相对于对对硝基苯基β-D-岩藻糖苷的水解活性，该酶对对硝基苯基β-D-葡萄糖苷和对硝基苯基β-D-半乳糖苷的水解能力分别为其32.0%和22.2%。对硝基苯基β-D-岩藻糖苷的水解活性受到D-岩藻糖的抑制，并受到D-葡萄糖、D-葡萄糖酸δ-内酯、D-半乳糖和D-半乳糖酸δ-内酯的微弱抑制。通过将这两种糖苷酶结合使用，柴胡皂苷a和b1通过相应的前柴胡皂苷元转化为它们的柴胡皂苷元。
