title: Solvent isotope and viscosity effects on the steady-state kinetics of the flavoprotein nitroalkane oxidase.
abstract: The flavoprotein nitroalkane oxidase catalyzes the oxidative denitrification of a broad range of primary and secondary nitroalkanes to yield the respective aldehydes or ketones, hydrogen peroxide and nitrite. With nitroethane as substrate the D2O(k(cat)/K(M)) value is 0.6 and the D2Ok(cat) value is 2.4. The k(cat) proton inventory is consistent with a single exchangeable proton in flight, while the k(cat)/K(M) is consistent with either a single proton in flight in the transition state or a medium effect. Increasing the solvent viscosity did not affect the k(cat) or k(cat)/K(M) value significantly, establishing that nitroethane binding is at equilibrium and that product release does not limit k(cat).
authors: Department of Chemistry and the Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA 30303, USA.
authors: Giovanni
authors: G
authors: Gadda
authors: Paul F
authors: PF
authors: Fitzpatrick
mesh_terms: D003903:Deuterium / Q000737:chemistry; D049308:Dioxygenases / Q000737:chemistry*; D057075:Enzyme Assays; D004980:Ethane / Q000031:analogs & derivatives / Q000737:chemistry; D005420:Flavoproteins / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry*; D005670:Fusarium / Q000201:enzymology*; D007700:Kinetics; D009595:Nitroparaffins / Q000737:chemistry; D010084:Oxidation-Reduction; D012997:Solvents / Q000737:chemistry; D014783:Viscosity
chemical_list: D005420:Flavoproteins; D005656:Fungal Proteins; D009595:Nitroparaffins; D012997:Solvents; C014705:nitroethane; D003903:Deuterium; D049308:Dioxygenases; C021876:2-nitropropane dioxygenase; D004980:Ethane
keywords: Flavoprotein; Michaelis–Menten kinetics; Nitroalkane oxidase; Solvent isotope effect; Viscosity
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