Reductive activation of nitrate reductases.
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.
Field
Sarah J
SJ
Centre for Metalloprotein Spectroscopy and Biology, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, UK NR4 7TJ.
Thornton
Nicholas P
NP
Anderson
Lee J
LJ
Gates
Andrew J
AJ
Reilly
Ann
A
Jepson
Brian J N
BJ
Richardson
David J
DJ
George
Simon J
SJ
Cheesman
Myles R
MR
Butt
Julea N
JN
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
D009565:Nitrate Reductases