title: Oxygen Delivery as a Limiting Factor in Modelling Dicopper(II) Oxidase Reactivity.
abstract: Deprotonation of ligand-appended alkoxyl groups in mononuclear copper(II) complexes of N,O ligands L1and L2, gave dinuclear complexes sharing symmetrical Cu2O2cores. Molecular structures of these mono- and binuclear complexes have been characterized by XRD, and their electronic structures by UV/Vis,1H NMR, EPR and DFT; moreover, catalytic performance as models of catechol oxidase was studied. The binuclear complexes with anti-ferromagnetically coupled copper(II) centers are moderately active in quinone formation from 3,5-di-tert-butyl-catechol under the established conditions of oxygen saturation, but are strongly activated when additional dioxygen is administered during catalytic turnover. This unforeseen and unprecedented effect is attributed to increased maximum reaction rates vmax, whereas the substrate affinity KMremains unaffected. Oxygen administration is capable of (partially) removing limitations to turnover caused by product inhibition. Because product inhibition is generally accepted to be a major limitation of catechol oxidase models, we think that our observations will be applicable more widely.
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Gülzow
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Hörner
authors.affiliation: Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476, Potsdam-Golm, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Strauch
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Stritt
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Irran
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Grohmann
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D002384:Catalysis; D004156:Catechol Oxidase / Q000737:chemistry* / Q000378:metabolism; D056831:Coordination Complexes / Q000737:chemistry* / Q000378:metabolism; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D013053:Spectrophotometry
chemical_list: D001672:Biocompatible Materials; D056831:Coordination Complexes; D003300:Copper; D004156:Catechol Oxidase; D010100:Oxygen
keywords: bubbly flows; copper; enzyme models; mass transfer; oxidases