Purification and characterization of an α-l-arabinofuranosidase, α-l-AFase, for hydrolyzed ginsenoside Rc from...

Natural ginsenoside needs to be converted into rare ginsenoside before it can be readily absorbed into the bloodstream for action. In this study, an α-l-arabinofuranosidase (α-l-AFase) gene Bsafs2 was cloned from Bacillus subtilis (B. subtilis). Bsafs2 was ligated to the expression vector pET28a(+), and the expression vector was constructed and transformed into Escherichia coli (E. coli) BL21 heterologous recombinant expression to obtain α-l-AFase. α-l-AFase can hydrolyze at the C₂₀ site of Ginsenoside Rc to obtain rare ginsenoside Rd. Studies on the enzymatic property showed that α-l-AFase had good tolerance to ethanol, glucose, and l-arabinose. The optimum temperature of α-l-AFase was 40 °C and pH = 5.5. Kinetic parameters K_m of α-l-AFase for pNPαAraf and Ginsenoside Rc were 1.93 and 8.9 mmol/L, the V_max were 26 and 154 μmol/min/mg, the K_cat were 24.14 and 1.48 S^-1, respectively. This study provides the enzyme source for the biotransformation of Ginsenoside Rc.