title: Control of cytochrome c oxidase activity by nitric oxide.
abstract: Over the past decade it was discovered that, over-and-above multiple regulatory functions, nitric oxide (NO) is responsible for the modulation of cell respiration by inhibiting cytochrome c oxidase (CcOX). As assessed at different integration levels (from the purified enzyme in detergent solution to intact cells), CcOX can react with NO following two alternative reaction pathways, both leading to an effective, fully reversible inhibition of respiration. A crucial finding is that the rate of electron flux through the respiratory chain controls the mechanism of inhibition by NO, leading to either a "nitrosyl" or a "nitrite" derivative. The two mechanisms can be discriminated on the basis of the differential photosensitivity of the inhibited state. Of relevance to cell pathophysiology, the pathway involving the nitrite derivative leads to oxidative degradation of NO, thereby protecting the cell from NO toxicity. The aim of this work is to review the information available on these two mechanisms of inhibition of respiration.
authors.affiliation: Department of Biochemical Sciences and CNR Institute of Molecular Biology and Pathology, University of Rome La Sapienza, Piazzale Aldo Moro 5, I-00185 Rome, Italy. maurizio.brunori@uniroma1.it
authors.forename: Maurizio
authors.initials: M
authors.lastname: Brunori
authors.forename: Alessandro
authors.initials: A
authors.lastname: Giuffrè
authors.forename: Elena
authors.initials: E
authors.lastname: Forte
authors.forename: Daniela
authors.initials: D
authors.lastname: Mastronicola
authors.forename: Maria Cecilia
authors.initials: MC
authors.lastname: Barone
authors.forename: Paolo
authors.initials: P
authors.lastname: Sarti
mesh_terms: D001665:Binding Sites; D003300:Copper / Q000737:chemistry; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D006418:Heme / Q000737:chemistry; D008954:Models, Biological; D009569:Nitric Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D009569:Nitric Oxide; D006418:Heme; D003300:Copper; D003576:Electron Transport Complex IV