title: Kinetic analysis of substrate inhibition in nitric oxide reductase of Paracoccus denitrificans.
abstract: The current kinetic model for the nitric oxide reductase reaction (Girsch, P., and de Vries, S. (1997) Biochim. Biophys. Acta 1318, 202-216) does not involve the concentration of an electron donor. Here we introduce this variable and show, both theoretically and experimentally, its role in determining the extent of substrate inhibition by the excess of nitric oxide. NO is found to inhibit competitively with the electron donor, possibly by binding to the oxidized form of the enzyme. The observed partial character of the inhibition is tentatively explained by a slow reduction of the non-productive NO complex.
authors.affiliation: Department of Biochemistry, Masaryk University, Kotlárská 2, Brno, CZ-61137, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Koutný
authors.forename: I
authors.initials: I
authors.lastname: Kucera
mesh_terms: D007700:Kinetics; D008956:Models, Chemical; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010231:Paracoccus denitrificans / Q000201:enzymology*; D013772:Tetramethylphenylenediamine / Q000378:metabolism
chemical_list: D009569:Nitric Oxide; D010088:Oxidoreductases; C034747:nitric-oxide reductase; D013772:Tetramethylphenylenediamine