title: Discovery of a Bacterial Glycoside Hydrolase Family 3 (GH3) β-Glucosidase with Myrosinase Activity from a Citrobacter Strain Isolated from Soil.
abstract: A Citrobacter strain (WYE1) was isolated from a UK soil by enrichment using the glucosinolate sinigrin as sole carbon source. The enzyme myrosinase was purified using a combination of ion exchange and gel filtration to give a pure protein of approximately 66 kDa. The N-terminal amino acid and internal peptide sequence of the purified protein were determined and used to identify the gene, which, based on InterPro sequence analysis, belongs to the family GH3, contains a signal peptide, and is a periplasmic protein with a predicted molecular mass of 71.8 kDa. A preliminary characterization was carried out using protein extracts from cell-free preparations. The apparent KM and Vmax were 0.46 mM and 4.91 mmol dm(-3) min(-1) mg(-1), respectively, with sinigrin as substrate. The optimum temperature and pH for enzyme activity were 25 °C and 6.0, respectively. The enzyme was marginally activated with ascorbate by a factor of 1.67.
authors.affiliation: Faculty of Life Sciences, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Abdulhadi
authors.initials: A
authors.lastname: Albaser
authors.affiliation: Faculty of Life Sciences, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Eleanna
authors.initials: E
authors.lastname: Kazana
authors.affiliation: Faculty of Life Sciences, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Bennett
authors.affiliation: Food and Health Programme, Institute of Food Research , Norwich NR4 7UA, United Kingdom.
authors.forename: Fatma
authors.initials: F
authors.lastname: Cebeci
authors.affiliation: Faculty of Life Sciences, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Vijitra
authors.initials: V
authors.lastname: Luang-In
authors.affiliation: Faculty of Life Sciences, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: Pietro D
authors.initials: PD
authors.lastname: Spanu
authors.affiliation: Faculty of Life Sciences, Imperial College London , London SW7 2AZ, United Kingdom.
authors.forename: John T
authors.initials: JT
authors.lastname: Rossiter
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002954:Citrobacter / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008970:Molecular Weight; D005810:Multigene Family; D012988:Soil Microbiology
chemical_list: D001426:Bacterial Proteins; D006026:Glycoside Hydrolases
keywords: bacteria; isothiocyanate; myrosinase; sequence