Identification and Characterization of a Mucilaginibacter sp. Strain QM49 β-Glucosidase and Its Use in the Production of the Pharmaceutically Active Minor Ginsenosides ( S )-Rh 1 and ( S )-Rg 2

• DOI: 10.1128/aem.01150-13
• Publication Date: 2013-06-29T07:38:20Z
• Authors: Chang-Hao Cui; Qing-Mei Liu; Jin-Kwang Kim; Bong-Hyun Sung; Song-Gun Kim; Sun-Chang Kim; Wan-Taek Im
• Keywords: Molecular mass

Here, we isolated and characterized a new ginsenoside-transforming β-glucosidase (BglQM) from Mucilaginibacter sp. strain QM49 that shows biotransformation activity for various major ginsenosides. The gene responsible this activity, bglQM, consists of 2,346 bp is predicted to encode 781 amino acid residues. This enzyme has molecular mass 85.6 kDa. Sequence analysis BglQM revealed it could be classified into glycoside hydrolase family 3. was overexpressed in Escherichia coli BL21(DE3) using maltose binding protein (MBP)-fused pMAL-c2x vector system containing the tobacco etch virus (TEV) proteolytic cleavage site. Overexpressed recombinant efficiently transform protopanaxatriol-type ginsenosides Re Rg1 (S)-Rg2 (S)-Rh1, respectively, by hydrolyzing one glucose moiety attached C-20 position at pH 8.0 30°C. Km values p-nitrophenyl-β-d-glucopyranoside, Re, were 37.0 ± 0.4 μM 3.22 0.15 1.48 0.09 mM, Vmax 33.4 0.6 μmol min(-1) mg(-1) 19.2 0.2 28.8 0.27 nmol protein, respectively. A crude ginsenoside mixture (PPTGM) treated with BglQM, followed silica column purification, produce (S)-Rh1 chromatographic purities 98% 0.5% 97% 1.2%, first report gram-scale production PPTGM novel