title: A thermostable humic acid peroxidase from Streptomyces sp. strain AH4: purification and biochemical characterization.
abstract: An extracellular thermostable humic acid peroxidase (HaP3) was isolated from a Streptomyces sp. strain AH4. MALDI-TOF MS analysis showed that the purified enzyme was a monomer with a molecular mass of 60,215.18Da. The 26N-terminal residues of HaP3 displayed high homology with Streptomyces peroxidases. Optimal peroxidase activity was obtained at pH 5 and 80°C. HaP3 was stable at pH and temperature ranges of 4-8 and 60-90°C for 72 and 4h, respectively. HaP3 catalyzed the oxidation of 2,4-dichlorophenol, commercial humic acid, guiacol, and 2,6-dichlorophenol (50mM); L-3,4-dihydroxyphenylalanine (40 mM); 4-chlorophenol, 2,4,5-trichlorophenol, and 2,4,6-trichlorophenol (30 mM) in the presence of hydrogen peroxide. Sodium azide and potassium cyanide inhibited HaP3, which indicated the presence of heme components. These properties make HaP3 a potential strong candidate for future application in the elimination of natural humic acids in drinking water.
authors.affiliation: Laboratory of Biochemistry and Industrial Microbiology (LBIM), Department of Industrial Chemistry, Faculty of Engineering Sciences, University of Saad Dahlab of Blida, B.P 270, 09000 Blida, Algeria.
authors.forename: Djamila
authors.initials: D
authors.lastname: Fodil
authors.forename: Bassem
authors.initials: B
authors.lastname: Jaouadi
authors.forename: Abdelmalek
authors.initials: A
authors.lastname: Badis
authors.forename: Zaraî Jaouadi
authors.initials: ZJ
authors.lastname: Nadia
authors.forename: Fatma Zohra
authors.initials: FZ
authors.lastname: Ferradji
authors.forename: Samir
authors.initials: S
authors.lastname: Bejar
authors.forename: Houcine
authors.initials: H
authors.lastname: Boutoumi
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010544:Peroxidases / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D013053:Spectrophotometry; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004791:Enzyme Inhibitors; D010544:Peroxidases