title: Redox couples of inducible nitric oxide synthase.
abstract: We report direct electrochemistry of the iNOS heme domain in a DDAB film on the surface of a basal plane graphite electrode. Cyclic voltammetry reveals FeIII/II and FeII/I couples at -191 and -1049 mV (vs Ag/AgCl). Imidazole and carbon monoxide in solution shift the FeIII/II potential by +20 and +62 mV, while the addition of dioxygen results in large catalytic waves at the onset of FeIII reduction. Voltammetry at higher scan rates (with pH variations) reveals that the FeIII/II cathodic peak can be resolved into two components, which are attributable to FeIII/II couples of five- and six-coordinate hemes. Digital simulation of our experimental data implicates water dissociation from the heme as a gating mechanism for ET in iNOS.
authors.affiliation: Department of Chemistry, Occidental College, Los Angeles, California 90041, USA.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Udit
authors.forename: Wendy
authors.initials: W
authors.lastname: Belliston-Bittner
authors.forename: Edith C
authors.initials: EC
authors.lastname: Glazer
authors.forename: Yen Hoang Le
authors.initials: YH
authors.lastname: Nguyen
authors.forename: James M
authors.initials: JM
authors.lastname: Gillan
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hill
authors.forename: Michael A
authors.initials: MA
authors.lastname: Marletta
authors.forename: David B
authors.initials: DB
authors.lastname: Goodin
authors.forename: Harry B
authors.initials: HB
authors.lastname: Gray
mesh_terms: D000818:Animals; D004579:Electron Transport; D006801:Humans; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D007501:Iron