Production of the Rare Ginsenosides Compound K, Compound Y, and Compound Mc by a Thermostable .BETA.-Glycosidase from Sulfolobus acidocaldarius

The rare ginsenosides compound K, compound Y, and compound Mc were produced from the major ginsenosides Rb(1), Rb(2), Rc, and Rd by a thermostable beta-glycosidase from Sulfolobus acidocaldarius via three pathways: Rb(1)-->Rd-->compound K, Rb(2)-->compound Y-->compound K, and Rc-->compound Mc. Each of the ginsenosides was identified by high-performance liquid chromatography using standards and liquid chromatography-mass spectrometry based on their molecular weights. The catalytic efficiency of the enzyme for ginsenosides followed the order Rb(1) (4.8)>Rc (4.5)>Rd (1.0)>Rb(2) (0.77 mM(-1) min(-1)). The enzyme converted 1 mg/ml reagent-grade Rb(1), Rb(2), and Rc to 0.53 mg/ml compound K, 0.56 mg/ml compound Y, and 0.70 mg/ml compound Mc, respectively, at pH 5.5 and 85 degrees C after 180 min, corresponding to mole conversion yields of 94, 80, and 100% (mol/mol), respectively. The enzyme converted the major ginsenosides Rb(1), Rb(2), Rc, and Rd in 10% (w/v) ginseng root extract to the rare ginsenosides with a mole yield of 99% after 24 h. These results suggest that beta-glycosidase from S. acidocaldarius can be used to produce compound K, compound Y, and compound Mc.