Purification and characterization of gypenoside-α-l-rhamnosidase hydrolyzing gypenoside-5 into ginsenoside Rd

In this paper, the gypenoside-α-(1→6)-l-rhamnosidase from microorganisms was purified and characterized. The enzyme hydrolyzed the 20-C, α-(1→6)-l-rhamnoside of gypenoside-5 to produce ginsenoside Rd, but did not hydrolyzed the α-rhamnoside of ginsenoside Rg2, and only partially hydrolyzed the α-rhamnoside of p-nitrophenyl-α-l-rhamnoside (pNPR) which was a hemi-cellulase substrate. The enzyme was purified to homogeneity by SDS polyacrylamide gel electrophoresis, and its molecular weight was about 68 kDa. The optimum temperature of enzyme reaction was 50 °C, and the optimum pH was 5. Metal ions activated the gypenoside-α-(1→6)-l-rhamnosidase activity.