title: Substrate specificity of β-glucosidase from Gordonia terrae for ginsenosides and its application in the production of ginsenosides Rg₃, Rg₂, and Rh₁ from ginseng root extract.
abstract: A β-glucosidase from Gordonia terrae was cloned and expressed in Escherichia coli. The recombinant enzyme with a specific activity of 16.4 U/mg for ginsenoside Rb1 was purified using His-trap chromatography. The purified enzyme specifically hydrolyzed the glucopyranosides at the C-20 position in protopanaxadiol (PPD)-type ginsenosides and hydrolyzed the glucopyranoside at the C-6 or C-20 position in protopanaxatriol (PPT)-type ginsenosides. The reaction conditions for the high-level production of Rg3 from Rb1 by the enzyme were pH 6.5, 30°C, 20 mg/ml enzyme, and 4 mg/ml Rb1. Under these conditions, G. terrae β-glucosidase completely converted Rb1 and Re to Rg3 and Rg2, respectively, after 2.5 and 8 h, respectively. Moreover, the enzyme converted Rg1 to Rh1 at 1 h with a molar conversion yield of 82%. The enzyme at 10 mg/ml produced 1.16 mg/ml Rg3, 1.47 mg/ml Rg2, and 1.17 mg/ml Rh1 from Rb1, Re, and Rg1, respectively, in 10% (w/v) ginseng root extract at pH 6.5 and 30°C after 33 h with molar conversion yields of 100%, 100%, and 77%, respectively. The combined molar conversion yield of Rg2, Rg3, and Rh1 from total ginsenosides in 10% (w/v) ginseng root extract was 68%. These above results suggest that this enzyme is useful for the production of ginsenosides Rg3, Rg2, and Rh1.
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.affiliation: Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea.
authors.forename: Hye-Ji
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Republic of Korea. Electronic address: deokkun@konkuk.ac.kr.
authors.forename: Deok-Kun
authors.initials: DK
authors.lastname: Oh
mesh_terms: D004926:Escherichia coli / Q000235:genetics; D036145:Ginsenosides / Q000096:biosynthesis* / Q000378:metabolism*; D033601:Gordonia Bacterium / Q000201:enzymology* / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D005894:Panax / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry*; D012502:Sapogenins / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D001617:beta-Glucosidase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D036145:Ginsenosides; D010936:Plant Extracts; D012502:Sapogenins; C097367:ginsenoside Rg3; C081552:protopanaxatriol; C425564:ginsenoside Rh1; C442759:ginsenoside Rb1; D001617:beta-Glucosidase; C062916:protopanaxadiol
keywords: Ginseng root extract; Ginsenosides Rg(3), Rg(2), and Rh(1); Gordonia terrae; Substrate specificity; β-Glucosidase