Nitric oxide inhibition of respiration involves both competitive (heme) and noncompetitive (copper) binding to cytochrome c oxidase.

ABSTRACT: NO reversibly inhibits mitochondrial respiration via binding to cytochrome c oxidase (CCO). This inhibition has been proposed to be a physiological control mechanism and/or to contribute to pathophysiology. Oxygen reacts with CCO at a heme iron:copper binuclear center (a(3)/Cu(B)). Reports have variously suggested that during inhibition NO can interact with the binuclear center containing zero (fully oxidized), one (singly reduced), and two (fully reduced) additional electrons. It has also been suggested that two NO molecules can interact with the enzyme simultaneously. We used steady-state and kinetic modeling techniques to reevaluate NO inhibition of CCO. At high flux and low oxygen tensions NO interacts predominantly with the fully reduced (ferrous/cuprous) center in competition with ox

SUBMITTER: Mason MG 

PROVIDER: S-EPMC1334642 | biostudies-literature | 2006 Jan

REPOSITORIES: biostudies-literature