title: Properties of NAD (P) H azoreductase from alkaliphilic red bacteria Aquiflexum sp. DL6.
abstract: Azoreductase plays a key role in bioremediation and biotransformation of azo dyes. It initializes the reduction of azo bond in azo dye metabolism under aerobic or anaerobic conditions. In the present study, we isolated an alkaliphilic red-colored Aquiflexum sp. DL6 bacterial strain and identified by 16S rRNA method. We report nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate-dependent azoreductase purified from Aquiflexum sp. DL6 by a combination of ammonium sulfate precipitation and chromatography methods. The azoreductase was purified up to 30-fold with 37 % recovery. The molecular weight was found to be 80 kDa. The optimum activity was observed at pH 7.4 and temperature 60 °C with amaranth azo dye as a substrate. The thermal stability of azoreductase was up to 80 °C. The azoreductase has shown a wide range of substrate specificity, including azo dyes and nitro aromatic compounds. Metal ions have no significant inhibitory action on azoreductase activity. The apparent K m and V max values for amaranth azo dye were 1.11 mM and 30.77 U/mg protein respectively. This NAD (P) H azoreductase represents the first azoreductase to be characterized from alkaliphilic bacteria.
authors.affiliation: Biochemistry Division, Department of Chemistry, University of Pune, Pune, 411 007, India, misalsantosh@gmail.com.
authors.forename: Santosh A
authors.initials: SA
authors.lastname: Misal
authors.forename: Devendra P
authors.initials: DP
authors.lastname: Lingojwar
authors.forename: Kachru R
authors.initials: KR
authors.lastname: Gawai
mesh_terms: D000548:Amaranth Dye / Q000378:metabolism; D000645:Ammonium Sulfate / Q000737:chemistry; D001391:Azo Compounds / Q000378:metabolism; D041963:Bacteroidetes / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D011232:Chemical Precipitation; D004795:Enzyme Stability; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D009249:NADP / Q000378:metabolism*; D009601:Nitroreductases; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001391:Azo Compounds; D009243:NAD; D009249:NADP; D000548:Amaranth Dye; D009247:NADH, NADPH Oxidoreductases; D009601:Nitroreductases; C021106:azoreductase; D000645:Ammonium Sulfate