Cytochrome c Oxidase Catalysis of the Reduction of Nitric Oxide to Nitrous Oxide
| Autor: | Xiao-Jian Zhao, Winslow S. Caughey, Vijaya Sampath |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
inorganic chemicals
Spectrophotometry Infrared Cyanide Nitrous Oxide Biophysics In Vitro Techniques Reductase Nitric Oxide Photochemistry Biochemistry Medicinal chemistry Catalysis Nitric oxide Electron Transport Electron Transport Complex IV chemistry.chemical_compound Electrochemistry Animals Cytochrome c oxidase Molecular Biology biology Ligand Myocardium Cell Biology Nitrous oxide Hydrogen-Ion Concentration equipment and supplies Models Chemical chemistry Yield (chemistry) biology.protein Cattle Oxidation-Reduction |
| Zdroj: | Biochemical and Biophysical Research Communications. 212:1054-1060 |
| ISSN: | 0006-291X |
| Popis: | Reduction of nitric oxide (NO) to nitrous oxide (N2O) is catalyzed by bovine heart cytochrome c oxidase (CcO) in anaerobic solutions at pH 7.2 and 20 degrees C. Cyanide inhibits and forms Fea3(3+)CN. The mononitrosyl (Fea3(2+)NO), but not the dinitrosyl (Fea3(2+)NO; CuB+NO), is a likely intermediate in N2O formation. One-electron reduction of NO at Fea3(2+) could yield N2O via HNO. However, a two-electron reduction of the NO ligand to give an intermediate that reacts with a second NO to give N2O and H2O appears more likely. Conversion of NO to N2O is favored by low levels of both NO and O2, higher NO levels can inhibit both cytochrome c oxidase and NO reductase activities. Raising the O2 level will favor catalysis of NO oxidation to NO2 by CcO. The reactions of NO and the specific CcO activity that occur in tissue will be critically dependent on NO, O2, and CcO levels. |
| Databáze: | OpenAIRE |
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