抄録
The purification method for a novel ginsenoside-hydrolyzing β-glucosidase from Paecilomyces Bainier sp. 229 was successfully simplified by the application of microcrystalline cellulose (MCC) as a novel chromatographic matrix. Only two chromatographic steps, Q-Sepharose FF and MCC column in sequence, were required to purify the enzyme to apparent homogeneity. The purified enzyme, with a native molecular weight estimated to be 305 KDa, was composed of three identical subunits of approximately 102 KDa each. The optimal enzyme activity was observed at pH 3.5 at 55 °C. It was stable within pH 3–7 and at temperatures lower than 50 °C. The optimal substrate for the enzyme was p-nitrophenyl-β-D-glucoside, followed by ginsenoside Rd, gentiobiose, and ginsenoside Rb1. It converted ginsenoside Rb1 to ginsenoside Rg3 specifically and efficiently. The hydrolyzing pathway of ginsenoside Rb1 by the enzyme was Rb1→Rd→Rg3. The specific activities against ginsenoside Rb1 and Rd were 56.7 μmol/min/mg and 129.4 μmol/min/mg respectively.
