酶法转化原人参二醇型皂苷为稀有人参皂苷C-K的研究

Enzymatic transformation of protopanoxadiol type saponins to minor ginsenoside C-K

通过比较PDA培养基和V8汁培养基对卵形孢霉产酶的影响,确定V8汁培养基培养卵形孢霉,糖苷酶活性更高。在该条件下培养卵形孢霉,通过DEAE-纤维素柱层析和30%～80%(NH4)2SO4沉淀,从其培养液中部分纯化出一种能够高效转化原人参二醇型皂苷为稀有人参皂苷C-K的糖苷酶GE-I。该酶转化人参皂苷Rb1、Rb2、Rc的途径分别为:Rb1→Rd→F2→C-K,Rb2→C-O→C-Y→C-K,Rc→Mb→Mc→C-K。GE-I最适pH为5.0,最适温度为45℃,在pH4.0～12.0和温度30～75℃范围内具有良好的稳定性。本研究为酶法制备稀有人参皂苷C-K奠定了一定的基础。

The effects of PDA medium and V8 juice medium on glycosidase activity produced by Oospora Wallr. were evaluated. The result showed that the glycosidase activity was higher in V8 juice medium. And then,a glycosidase GE-I was partially purified from culture filtrate of Oospora Wallr. incubated in V8 juice medium by DEAE-cellulose column chromatography and 30%N80% （NH4）2SO4 precipitate. GE-I could efficiently convert protopanoxadiol type saponins to minor ginsenosides C-K. The transformation pathways of Rbl,Rb2 and Rc by this enzyme were Rb1→Rd→F2→C-K, Rb2→CO→CY→C-K, Rc→Mb→Mc→C-K, respectively. The optimal pH and temperature of GE-I were pH5.0 and 45℃ respectively. GE-I was highly stable within pH4.0-11.0 and 30-75℃. This study laid a certain foundation of the enzymatic preparation of minor ginsenoside C-K.