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

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 C ₂₀ 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.
Competing Interests: Declaration of competing interest Ling Zhu declares that she has no conflict of interest. Weiliang Liu declares that he has no conflict of interest. Qihe Xu declares that he has no conflict of interest. Lifang Zhang declares that he has no conflict of interest. Qingfang Xu declares that he has no conflict of interest. Xiu Gao declares that he has no conflict of interest. Jian Cai declares that he has no conflict of interest.
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