title: Characterization of the Proton-Translocating Cytochrome c Oxidase Activity in the Plasma Membrane of Intact Anacystis nidulans Spheroplasts.
abstract: Intact spheroplasts of the cyanobacterium (blue-green alga) Anacystis nidulans oxidized various exogenous c-type cytochromes with concomitant outward proton translocation while exogenous ferricytochrome c was not reduced. The H(+)/e(-) stoichiometry was close to 1 with each of the cytochromes and did not depend on the actual rate of the oxidase reaction. Observed proton ejections were abolished by the uncoupler carbonyl cyanide m-chlorophenylhydrazone. Cyanide, azide, and carbon monoxide inhibited cytochrome c oxidation and proton extrusion in parallel while dicyclohexylcarbodiimide affected proton translocation more strongly than cytochrome c oxidation. The cytoplasmic membrane of A. nidulans appears to contain a proton-translocating cytochrome c oxidase similar to the one described for mitochondria.
authors: Biophysical Chemistry Group, Institute of Physical Chemistry, University of Vienna, Währingerstrasse 42, A-1090 Vienna, Austria.
authors: G A
authors: GA
authors: Peschek