title: Reductive activation of nitrate reductases.
abstract: Protein film voltammetry of Paracoccus pantotrophus respiratory nitrate reductase (NarGH) and Synechococcus elongatus assimilatory nitrate reductase (NarB) shows that reductive activation of these enzymes may be required before steady state catalysis is observed. For NarGH complementary spectroscopic studies suggest a structural context for the activation. Catalytic protein film voltammetry at a range of temperatures has allowed quantitation of the activation energies for nitrate reduction. For NarGH with an operating potential of ca. 0.05 V the activation energy of ca. 35 kJ mol-1 is over twice that measured for NarB whose operating potential is ca. -0.35 V.
authors.affiliation: Centre for Metalloprotein Spectroscopy and Biology, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK NR4 7TJ.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Field
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Thornton
authors.forename: Lee J
authors.initials: LJ
authors.lastname: Anderson
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Gates
authors.forename: Ann
authors.initials: A
authors.lastname: Reilly
authors.forename: Brian J N
authors.initials: BJ
authors.lastname: Jepson
authors.forename: David J
authors.initials: DJ
authors.lastname: Richardson
authors.forename: Simon J
authors.initials: SJ
authors.lastname: George
authors.forename: Myles R
authors.initials: MR
authors.lastname: Cheesman
authors.forename: Julea N
authors.initials: JN
authors.lastname: Butt
mesh_terms: D001665:Binding Sites; D002384:Catalysis; D004578:Electron Spin Resonance Spectroscopy; D004789:Enzyme Activation; D009565:Nitrate Reductases / Q000737:chemistry* / Q000378:metabolism*; D010084:Oxidation-Reduction; D042084:Paracoccus pantotrophus / Q000201:enzymology; D017550:Spectroscopy, Fourier Transform Infrared; D046940:Synechococcus / Q000201:enzymology
chemical_list: D009565:Nitrate Reductases