title: Characterization of β-xylosidase from Thermoanaerobacterium thermosaccharolyticum and its application to the production of ginsenosides Rg1 and Rh 1 from notoginsenosides R 1 and R 2.
abstract: β-Xylosidase from Thermoanaerobacterium thermosaccharolyticum was purified by His-trap affinity chromatography giving a specific activity of 5.15 U mg(-1). From gel-filtration chromatography, the purified enzyme was a tetramer with a total molecular mass of 245 kDa. Maximal enzyme activity using o-nitrophenyl(NP)-β-D-xylopyranoside was at pH 6.5 and 60 °C, with a half-life of 50 h. The enzyme had highest activity for oNP-β-D-xylopyranoside among aryl-glycosides, and was only active for notoginsenosides R1 and R2 amongst various ginsenosides. β-Xylosidase completely converted 2 g notoginsenosides R1 and R2 l(-1) to 1.69 g ginsenoside Rg1 l(-1) and 1.63 g ginsenoside Rh1 l(-1) in 4 and 18 h, respectively, with molar conversion yields of 100 % and specific productivities of 0.21 and 0.05 g g-enzyme(-1) h(-1), respectively. To our knowledge, this is the first report on the enzymatic production of ginsenosides Rg1 and Rh1 from notoginsenosides R1 and R2.
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: Kyung-Chul
authors.initials: KC
authors.lastname: Shin
authors.forename: Min-Ju
authors.initials: MJ
authors.lastname: Seo
authors.forename: Deok-Kun
authors.initials: DK
authors.lastname: Oh
mesh_terms: D001711:Biotransformation; D036145:Ginsenosides / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature; D046950:Thermoanaerobacterium / Q000201:enzymology* / Q000235:genetics; D014995:Xylosidases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D036145:Ginsenosides; D011994:Recombinant Proteins; D014995:Xylosidases; C026579:exo-1,4-beta-D-xylosidase