Evidence for a photoactivation of CO rebinding to fully reduced cytochrome c oxidase after low-temperature flash photolysis.
Carbon monoxide rebinding to isolated fully reduced cytochrome c oxidase has been investigated by low-temperature, flash photolysis, dual-wavelength spectrometry. By using separately different wavelength pairs to monitor the liganding of CO to Fe a3 and by keeping all other experimental conditions identical, there has been singled out a photoactivation effect on CO rebinding. For instance, at 187 K, the rate constant of CO rebinding observed at 425-475 nm was twice that derived from the kinetic at 444-475 nm despite a rate constant of photodissociation about 10 times larger at 425-475 nm than at 444-475 nm. This new finding is discussed with respect to previous investigations under similar conditions.
Denis
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M
Neau
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D000818:Animals; D002248:Carbon Monoxide / Q000378:metabolism*; D002417:Cattle; D003080:Cold Temperature; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D009206:Myocardium / Q000201:enzymology; D010777:Photochemistry; D010782:Photolysis; D013053:Spectrophotometry
D002248:Carbon Monoxide; D007501:Iron; D003576:Electron Transport Complex IV