title: Reactions of the class II peroxidases, lignin peroxidase and Arthromyces ramosus peroxidase, with hydrogen peroxide. Catalase-like activity, compound III formation, and enzyme inactivation.
abstract: The reactions of the fungal enzymes Arthromyces ramosus peroxidase (ARP) and Phanerochaete chrysosporium lignin peroxidase (LiP) with hydrogen peroxide (H(2)O(2)) have been studied. Both enzymes exhibited catalase activity with hyperbolic H(2)O(2) concentration dependence (K(m) approximately 8-10 mm, k(cat) approximately 1-3 s(-1)). The catalase and peroxidase activities of LiP were inhibited within 10 min and those of ARP in 1 h. The inactivation constants were calculated using two independent methods; LiP, k(i) approximately 19 x 10(-3) s(-1); ARP, k(i) approximately 1.6 x 10(-3) s(-1). Compound III (oxyperoxidase) was detected as the majority species after the addition of H(2)O(2) to LiP or ARP, and its formation was accompanied by loss of enzyme activity. A reaction scheme is presented which rationalizes the turnover and inactivation of LiP and ARP with H(2)O(2). A similar model is applicable to horseradish peroxidase. The scheme links catalase and compound III forming catalytic pathways and inactivation at the level of the [compound I.H(2)O(2)] complex. Inactivation does not occur from compound III. All peroxidases studied to date are sensitive to inactivation by H(2)O(2), and it is suggested that the model will be generally applicable to peroxidases of the plant, fungal, and prokaryotic superfamily.
authors: Departamento de Biologia Vegetal (Fisiologia Vegetal) and the Departamento de Bioquimica y Biologia Molecular-A, Universidad de Murcia, Espinardo, Murcia E-30100, Spain.
authors: Alexander N P
authors: AN
authors: Hiner
authors: Josefa
authors: J
authors: Hernández-Ruiz
authors: José Neptuno
authors: JN
authors: Rodríguez-López
authors: Francisco
authors: F
authors: García-Cánovas
authors: Nigel C
authors: NC
authors: Brisset
authors: Andrew T
authors: AT
authors: Smith
authors: Marino B
authors: MB
authors: Arnao
authors: Manuel
authors: M
authors: Acosta
mesh_terms: D002374:Catalase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005656:Fungal Proteins / Q000378:metabolism; D005658:Fungi / Q000201:enzymology*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008954:Models, Biological; D008956:Models, Chemical; D010100:Oxygen / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D013997:Time Factors
chemical_list: D005656:Fungal Proteins; D011994:Recombinant Proteins; D006861:Hydrogen Peroxide; D010544:Peroxidases; C042858:lignin peroxidase; D002374:Catalase; D009195:Peroxidase; D010100:Oxygen