Enzyme kinetics of ginsenosidase type IV hydrolyzing 6-O-multi-glycosides of protopanaxatriol type ginsenosides

In this work, the kinetics of ginsenosidase type IV hydrolyzing the 6-O-multi-glycosides of protopanaxatriol type ginsenosides (PPT) from Aspergillus sp.39g strain were investigated. The enzyme molecular weight was about 56 kDa. The enzyme hydrolyzes the 6-O-α-l-(1 → 2)-rhamnoside of ginsenoside Re and 6-O-β-d-(1 → 2)-xyloside of R1 into Rg1, and subsequently hydrolyzes 6-O-β-d-glucoside of Rg1 into F1. The enzyme hydrolyzes 6-O-α-l-(1 → 2)-rhamnoside of Rg2 and 6-O-β-d-(1 → 2)-glucoside of Rf into Rh1, and subsequently hydrolyzes 6-O-β-d-glucoside of Rh1 into its aglycone. The enzyme Km and Vmax for Re were 22.2 mM, and 7.94 mM/h; the Km and Vmax for R1 were 7.06 mM and 1.61 mM/h; the enzyme transformation velocity (V0) at 5 mM substrate was 1.46 mM/h for Re, and 0.67 mM/h for R1. Therefore, the enzyme hydrolysis on the Re rhamnoside was faster than that on R1 xyloside. The enzyme V0 on Rg1 was 0.05 mM/h that indicated the enzyme hardly hydrolyzed the 6-O-β-d-glucoside of Rg1. The enzyme kinetic parameters of Rg2 and Rf were 5.74 and 9.43 mM for Km; 2.70 and 2.84 mM/h for Vmax; 1.26 and 0.98 mM/h for V0 at 5 mM substrate, respectively. Thus the enzyme hydrolysis on Rg2 rhamnoside was faster than that on the glucoside of Rf.

► We investigate the kinetics of a novel ginsenosidase type IV.
► We investigate the hydrolysis of the enzyme on multi substrates.
► We investigate a novel ginsenosidase Type IV hydrolysis on multi-glycoside.