Biotransformation pathway and kinetics of the hydrolysis of the 3-O- and 20-O-multi-glucosides of PPD-type ginsenosides by ginsenosidase type I

• Ginsenosidase type I can hydrolyze 3-O and 20-O-multi-glycosides of PPD ginsenoside.
• Enzyme hydrolyzed Rb1 and Rb3 with two pathways hydrolyzing 20-O and 3-O-glycosides.
• Hydrolyzing 20-O-glycoside speed of Rb1 and Rb3 was faster than that of 3-O-Glc.
• Enzyme firstly hydrolyzes 3-O-glucoside of Rb2 and Rc, then hydrolyzes 20-O-glycoside.
• Enzyme reaction speed: Rb3 to Rd>Rb1 to Rd>Rc>Rb2>Rd>Rb3 to C-Mx1>Rb1 to Gyp17>F2>Rg3>.

Ginsenosidase type I from Aspergillus niger g.48 can hydrolyze the 3-O- and 20-O-multi-glycosides of PPD-type ginsenosides. The enzyme molecular weight is approximately 74 kDa. When hydrolyzing the glycosides of Rb1, Rb3, Rb2 and Rc, the structures of which only differ in their terminal 20-O-glycosides, ginsenosidase type I hydrolyzes both the 3-O- and 20-O-glycosides of Rb1 and Rb3 using two pathways, but the enzyme first hydrolyzes the 3-O-glucosides of Rb2 and Rc using one pathway. One pathway of Rb1 hydrolyzes the 20-O-Glc of Rb1 to Rd→F2→C-K; another pathway hydrolyzes the 3-O-Glc of Rb1 to Gyp17→Gyp75→C-K. Two hydrolysis pathways are used to hydrolyze the 20-O-Xyl and the 3-O-Glc of Rb3. According to the enzyme reaction parameters Km, Vmax and V0 at a 10 mM substrate concentration, the enzyme hydrolysis velocity values decrease in the following order: the 20-O-Xyl of Rb3→Rd> the 20-O-Glc of Rb1→Rd> the 3-O-Glc of Rc> the 3-O-Glc of Rb2> the 3-O-Glc of Rd> the 3-O-Glc of Rb3→C-Mx1> the 3-O-Glc of Rb1→Gyp17> the 3-O-Glc of F2> the 3-O-Glc of 20(S)-Rg3.