title: Purification and partial characterization of azoreductase from Enterobacter agglomerans.
abstract: Azoreductase, an enzyme catalyzing the reductive cleavage of the azo bond of methyl red (MR) and related dyes, was purified to electrophoretic homogeneity from Enterobacter agglomerans. This bacterial strain, isolated from dye-contaminated sludge, has a higher ability to grow, under aerobic conditions, on culture medium containing 100mg/L of MR. The enzyme was purified approximately 90-fold with 20% yield by ammonium sulfate precipitation, followed by three steps of column chromatography (gel-filtration, anion-exchange, and dye-affinity). The purified enzyme is a monomer with a molecular weight of 28,000 Da. The maximal azoreductase activity was observed at pH 7.0 and at 35 degrees C. This activity was NADH dependent. The K(m) values for both NADH and MR were 58.9 and 29.4 microM, respectively. The maximal velocity (V(max)) was 9.2 micromol of NADH min(-1)mg(-1). The purified enzyme is inhibited by several metal ions including Fe(2+) and Cd(2+).
authors.affiliation: Unit of Bio-industry and Molecular Toxicology, Laboratory of Microbiology, Biotechnology and Environment, Faculty of Sciences Aïn Chock, University Hassan II-Aïn Chock, Km 8 route d'El Jadida, B.P. 5366 Mâarif, Casablanca, Morocco. moutaouakkil@hotmail.com
authors.forename: Adnane
authors.initials: A
authors.lastname: Moutaouakkil
authors.forename: Youssef
authors.initials: Y
authors.lastname: Zeroual
authors.forename: Fatima
authors.initials: F
authors.lastname: Zohra Dzayri
authors.forename: Mohamed
authors.initials: M
authors.lastname: Talbi
authors.forename: Kangmin
authors.initials: K
authors.lastname: Lee
authors.forename: Mohamed
authors.initials: M
authors.lastname: Blaghen
mesh_terms: D001391:Azo Compounds / Q000378:metabolism; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000494:pharmacology; D004396:Coloring Agents / Q000378:metabolism; D004754:Enterobacter / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000494:pharmacology; D007700:Kinetics; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D009601:Nitroreductases; D012722:Sewage / Q000382:microbiology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D004791:Enzyme Inhibitors; D012722:Sewage; D002104:Cadmium; D009243:NAD; C008492:methyl red; D007501:Iron; D009247:NADH, NADPH Oxidoreductases; D009601:Nitroreductases; C021106:azoreductase