The cytochrome cbb3 from Pseudomonas stutzeri displays nitric oxide reductase activity.
The cytochrome cbb3 is an isoenzyme in the family of cytochrome c oxidases. This protein purified from Pseudomonas stutzeri displays a cyanide-sensitive nitric oxide reductase activity (Vmax=100+/-9 mol NO x mol cbb3(-1) x min(-1) and Km=12+/-2.5 microm), which is lost upon denaturation. This enzyme is only partially reduced by ascorbate, and readily re-oxidized by NO under anaerobic conditions at a rate consistent with the turnover number for NO consumption. As shown by transient spectroscopy experiments and singular value decomposition (SVD) analysis, these results suggest that the cbb3-type cytochromes, sharing structural features with bacterial nitric oxide reductases, are the enzymes retaining the highest NO reductase activity within the heme-copper oxidase superfamily.
Forte
E
E
Department of Biochemical Sciences and CNR Centre of Molecular Biology, University of Rome 'La Sapienza', Rome, Italy.
Urbani
A
A
Saraste
M
M
Sarti
P
P
Brunori
M
M
Giuffrè
A
A
D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology*; D013057:Spectrum Analysis
D009569:Nitric Oxide; D010088:Oxidoreductases; C034747:nitric-oxide reductase; C414443:cbb3 oxidase; D003576:Electron Transport Complex IV