Control of respiration by cytochrome c oxidase in intact cells: role of the membrane potential (Articolo in rivista)

Type
Label
  • Control of respiration by cytochrome c oxidase in intact cells: role of the membrane potential (Articolo in rivista) (literal)
Anno
  • 2009-01-01T00:00:00+01:00 (literal)
Alternative label
  • Dalmonte ME; Forte E; Genova ML; Giuffrè A; Sarti P; Lenaz G (2009)
    Control of respiration by cytochrome c oxidase in intact cells: role of the membrane potential
    in The Journal of biological chemistry (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Dalmonte ME; Forte E; Genova ML; Giuffrè A; Sarti P; Lenaz G (literal)
Pagina inizio
  • 32331 (literal)
Pagina fine
  • 32335 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 284 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Department of Biochemical Sciences, Sapienza University of Rome and Institute of Molecular Biology and Pathology, National Research Council, I-00185 Rome, Italy, and Department of Biochemistry, University of Bologna, I-40126 Bologna, Italy (literal)
Titolo
  • Control of respiration by cytochrome c oxidase in intact cells: role of the membrane potential (literal)
Abstract
  • Metabolic control analysis was applied to intact HepG2 cells. The effect on the control coefficient of cytochrome c oxidase (CcOX) over cell respiration of both the electrical (Delta-psi??) and chemical (Delta-?pH) component of the mitochondrial transmembrane proton electrochemical gradient (Delta-muH) was investigated. The overall O2 consumption and specific CcOX activity of actively phosphorylating cells were titrated with cyanide under conditions in which ??Delta-psi and Delta-?pH were selectively modulated by addition of ionophores. In the absence of ionophores, CcOX displayed a high control coefficient (CIV = ?0.73), thus representing an important site of regulation of mitochondrial oxidative phosphorylation. A high control coefficient value (CIV ? = 0.85) was also measured in the presence of nigericin, i.e., when ??Delta-muH is maximal, and in the presence of nigericin and valinomycin (CIV ?= 0.77), when Delta-mu??H? is abolished. In contrast, CcOX displayed a markedly lower control coefficient (CIV ? = 0.30) upon addition of valinomycin, when ??Delta-psi is converted into Delta-?pH. These results show that Delta-psi ??is responsible for the tight control of CcOX over respiration in actively phosphorylating cells. (literal)
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