title: A study on reducing substrates of manganese-oxidizing peroxidases from Pleurotus eryngii and Bjerkandera adusta.
abstract: A novel peroxidase, oxidizing Mn2+ and different aromatic compounds, was isolated. Hydroquinones, substituted phenols, dyes, other aromatic compounds and Mn2+ were compared as reducing substrates, and conclusions presented in the light of a molecular model built by homology modeling. The enzymes showed the fastest reaction rates with Mn2+, but the highest affinity corresponded to hydroquinones and dyes. Oxidation of Reactive Black 5 (an azo-dye not oxidized by Mn3+) was non-competitively inhibited by Mn2+. These findings, together with identification of putative Mn-binding site (involving Glu36, Glu40, Asp175 and inner heme propionate) and long-range electron transfer pathways, indicate that different sites are involved in substrate oxidation.
authors.affiliation: FG Microbial Ecology, Technical University of Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Heinfling
authors.forename: F J
authors.initials: FJ
authors.lastname: Ruiz-Dueñas
authors.forename: M J
authors.initials: MJ
authors.lastname: Martínez
authors.forename: M
authors.initials: M
authors.lastname: Bergbauer
authors.forename: U
authors.initials: U
authors.lastname: Szewzyk
authors.forename: A T
authors.initials: AT
authors.lastname: Martínez
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D001665:Binding Sites; D002852:Chromatography, Ion Exchange; D006418:Heme; D006841:Hydrocarbons, Aromatic / Q000378:metabolism; D007700:Kinetics; D008345:Manganese / Q000378:metabolism; D008958:Models, Molecular; D010544:Peroxidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011124:Polyporaceae / Q000201:enzymology*; D011487:Protein Conformation; D013379:Substrate Specificity
chemical_list: D006841:Hydrocarbons, Aromatic; D006418:Heme; D008345:Manganese; D010544:Peroxidases; C051129:manganese peroxidase