Nitric oxide inhibits the cytochrome oxidase but not the alternative oxidase of plant mitochondria.
Oxygen consumption via the cytochrome pathway in isolated soybean (Glycine max [L.] Merr.) cotyledon mitochondria was inhibited by nitric oxide (NO) while respiration via the cyanide-insensitive alternative oxidase was not significantly affected. Inhibition of cytochrome pathway activity was rapidly reversible upon depletion of the added NO. NO production was also detected in solutions of NaNO2 plus ascorbate and the extent of cytochrome pathway inhibition was dependent on the NO2- concentration. Little inhibition of alternative pathway respiration was observed under similar conditions. The alternative oxidase may play a role in nitric oxide tolerance in higher plants and in organisms such as trypanosomes which contain a plant-like alternative oxidase.
Millar
A H
AH
Division of Biochemistry and Molecular Biology, and The Cooperative Research Centre for Plant Science, Australian National University, Canberra.
Day
D A
DA
D001205:Ascorbic Acid / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology*; D024101:Mitochondrial Proteins; D009243:NAD / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D010940:Plant Proteins / Q000037:antagonists & inhibitors; D012977:Sodium Nitrite / Q000494:pharmacology; D013025:Glycine max / Q000201:enzymology*; D000099188:Alternative Oxidase
D001205:Ascorbic Acid; D003576:Electron Transport Complex IV; D024101:Mitochondrial Proteins; D009243:NAD; D009569:Nitric Oxide; D010088:Oxidoreductases; D010940:Plant Proteins; D012977:Sodium Nitrite; D000099188:Alternative Oxidase