A ginseng saponin (GS) Rb, -hydrolytic enzyme (3-glucosidase (F-I) was partially purified from cultural broth of the phylopalhogenic fungus Cylindrocarpon destructans by DEAE-eellulose anion exchange chromatography, 30% -80% (NH4)2SO4 salting-out, Sepharose CL-6B gel filtration chromatography and Mono Q HR 5/5 anion exchange chromatography. F-I had fairly good pH and thermal stability, within the range of pH 4.0 ~ 11. 0 and below 55 t , it demeaned fine f3-glucosidase activity. The optimal pH and temperature of F-I were pH 5. 0 and 55 *C respectively. EDTA, Zn2* , and Cu2* inhibited strongly against its activity. Specificity analysis of substratum indicated that F-I could highly hydrolyze artificial synthetically substratum of />NPG, it could also hydrolyze disaccharides such as cellobiose and gentiobiose that linked by p-glucoside bond, thus explained that it was a p-glucosidase. F-I acquitted itself well as fairly strong hydrolysis activity on GS, but had low hydrolysis activity on Rb2 and Re. The pathway of hydrolysis of GS was Rb,-? Rd - F2-? C-K. The high effective hydrolysis of F-I on GS laid a foundation for rare GS Rb, preparation industry.%通过DEAE-纤维素阴离子交换层析、30％ -80％ (NH4)2SO4盐析、Sepharose CL-6B凝胶过滤层析和Mono Q HR 5/5阴离子交换层析,从毁灭柱孢菌培养液中部分纯化出一种能够水解人参皂苷Rb1的β-葡萄糖苷酶F-I.F-I具有较好的pH稳定性和热稳定性,在pH4.0-11.0范围内和55℃以下表现出良好的β-葡萄糖苷酶活性,其最适pH为5.0,最适温度为55℃.EDTA、Cu2+和Zn2+对该酶活性有较强的抑制作用.底物专一性分析表明,F-I能高特异性水解人工合成的底物pNPG,还能水解β-葡萄糖苷键连接的二糖如纤维二糖和龙胆二糖,说明此酶为一种β-葡萄糖苷酶.F-I对人参皂苷Rb1表现了较强的水解活性,而对人参皂苷Rb2和Rc的水解活性较低.该酶水解人参皂苷Rb1的路径为Rb1→Rd→F2→C-K.F-I对人参皂苷Rb1的这种高效水解为稀有人参皂苷的工业制备奠定了基础.
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