Cytochrome c Oxidase of the Cyanobacterium Phormidium foveolarum
2014
Häfele, Ursula | Scherer, Siegfried | Böger, Peter
Phormidium foveolarum was grown with nitrate or ammonia as nitrogen source. With ammonia present respiration increased by a factor of 4 due to increase of cytochrome c oxidase. The inhibition of respiration by cyanide was measured during the growth period, indicating that only one terminal oxidase is present in Phormidium foveolarum . Cytochrome c oxidase from ammonia-grown filaments was solubilized and purified on phenylsuperose and by anion exchange 100-fold com pared to the crude cell extract. The difference spectrum (oxidized minus reduced) shows absorption peaks at 417 nm, 514 -520 nm. 550 nm and 605 nm. These maxima, together with a low inhibition constant for cyanide (Kᵢ = 0.4 μᴍ) and a higher one for azide (kᵢ= 1.75 mᴍ) are interpreted in terms of an αα₃-type cytochrome c oxidase present containing noncovalently-bound cytochrome c.
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