scholarly journals Oscillations of nitric oxide concentration in the perturbed denitrification pathway of Paracoccus denitrificans

1992 ◽  
Vol 286 (1) ◽  
pp. 111-116 ◽  
Author(s):  
I Kučera
Keyword(s):  
Nitric Oxide ◽  
Paracoccus Denitrificans ◽  
Reductase Activity ◽  
Membrane Vesicles ◽  
Inhibitory Effect ◽  
Nitric Oxide Reductase ◽  
Sustained Oscillations ◽  
Carbonyl Cyanide ◽  
Oxide Concentration ◽  
Nitric Oxide Concentration

The metabolism of nitric oxide in Paracoccus denitrificans has been studied using a Clark-type electrode. The uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP) and the SH reagent N-ethylmaleimide, both of which released nitric oxide from cells respiring nitrite, were found to be efficient inhibitors of nitric oxide reductase activity. Control experiments with another uncoupler, pentachlorophenol, showed that the inhibitory effect of CCCP was not the result of a decrease in membrane potential. The denitrification pathway in cells with partly inhibited nitric oxide reductase, or in a reconstituted system containing purified nitric reductase and membrane vesicles, exhibited marked sustained oscillations of nitric oxide concentration. The occurrence of the oscillations was strictly dependent on the initial concentration of nitrite. The observed oscillatory kinetics is considered to reflect two regulatory signals destabilizing the denitrification pathway, namely the inhibition of nitric oxide reductase by nitric oxide and/or by nitrite.

Effect of round window membrane application of nitric oxide on hearing and nitric oxide concentration in perilymph

2003 ◽  
Vol 67 (6) ◽  
pp. 585-590 ◽  
Author(s):  
Jonathan B. Hanson ◽  
Paul T. Russell ◽  
Andy T.A. Chung ◽  
Claire S. Kaura ◽  
Samantha H. Kaura ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Round Window ◽  
Round Window Membrane ◽  
Oxide Concentration ◽  
Nitric Oxide Concentration

scholarly journals A new assay for nitric oxide reductase reveals two conserved glutamate residues form the entrance to a proton-conducting channel in the bacterial enzyme

2006 ◽  
Vol 401 (1) ◽  
pp. 111-119 ◽  
Author(s):  
Faye H. Thorndycroft ◽  
Gareth Butland ◽  
David J. Richardson ◽  
Nicholas J. Watmough
Keyword(s):  
Nitric Oxide ◽  
Paracoccus Denitrificans ◽  
Nitric Oxide Reductase ◽  
Transmembrane Helices ◽  
Level Of Activity ◽  
Bacterial Enzyme ◽  
Cytoplasmic Membranes ◽  
Membrane Bound ◽  
Proton Movement ◽  
High Level

A specific amperometric assay was developed for the membrane-bound NOR [NO (nitric oxide) reductase] from the model denitrifying bacterium Paracoccus denitrificans using its natural electron donor, pseudoazurin, as a co-substrate. The method allows the rapid and specific assay of NO reduction catalysed by recombinant NOR expressed in the cytoplasmic membranes of Escherichia coli. The effect on enzyme activity of substituting alanine, aspartate or glutamine for two highly conserved glutamate residues, which lie in a periplasmic facing loop between transmembrane helices III and IV in the catalytic subunit of NOR, was determined using this method. Three of the substitutions (E122A, E125A and E125D) lead to an almost complete loss of NOR activity. Some activity is retained when either Glu122 or Glu125 is substituted with a glutamine residue, but only replacement of Glu122 with an aspartate residue retains a high level of activity. These results are interpreted in terms of these residues forming the mouth of a channel that conducts substrate protons to the active site of NOR during turnover. This channel is also likely to be that responsible in the coupling of proton movement to electron transfer during the oxidation of fully reduced NOR with oxygen [U. Flock, N. J. Watmough and P. Ädelroth (2005) Biochemistry 44, 10711–10719].

scholarly journals Nasal nitric oxide concentration in paranasal sinus inflammatory diseases

1999 ◽  
Vol 13 (2) ◽  
pp. 307-312 ◽  
Author(s):  
J-F. Arnal ◽  
P. Flores ◽  
J. Rami ◽  
M Murris-Espin ◽  
F Bremont ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Paranasal Sinus ◽  
Inflammatory Diseases ◽  
Nasal Nitric Oxide ◽  
Oxide Concentration ◽  
Nitric Oxide Concentration

Effect of Initial Nitric Oxide Concentration on Outcome in Infants with Persistent Pulmonary Hypertension of the Newborn

Neonatology ◽  
1999 ◽  
Vol 75 (4) ◽  
pp. 215-224 ◽  
Author(s):  
Karen S. Wood ◽  
Martin J. McCaffrey ◽  
Jocelyn C. Donovan ◽  
Alan D. Stiles ◽  
Carl L. Bose
Keyword(s):  
Nitric Oxide ◽  
Pulmonary Hypertension ◽  
Persistent Pulmonary Hypertension ◽  
Oxide Concentration ◽  
Nitric Oxide Concentration
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