Dalmonte 2009 J Biol Chem: Difference between revisions
No edit summary |
No edit summary |
||
Line 1: | Line 1: | ||
{{Publication | {{Publication | ||
|title=Dalmonte ME, Forte E, Genova ML, Giuffrรจ A, Sarti P, Lenaz G (2009) Control of respiration by cytochrome c oxidase in intact cells: role of the membrane potential. J. Biol. Chem. 284(47):32331-5. | |title=Dalmonte ME, Forte E, Genova ML, Giuffrรจ A, Sarti P, Lenaz G (2009) Control of respiration by cytochrome c oxidase in intact cells: role of the membrane potential. J. Biol. Chem. 284(47):32331-5. | ||
|info=[http://www.ncbi.nlm.nih.gov/pubmed/19776013 PMID: 19776013] | |||
|authors=Dalmonte ME, Forte E, Genova ML, Giuffre A, Sarti P, Lenaz G | |authors=Dalmonte ME, Forte E, Genova ML, Giuffre A, Sarti P, Lenaz G | ||
|year=2009 | |year=2009 | ||
Line 6: | Line 7: | ||
|abstract=Metabolic control analysis was applied to intact HepG2 cells. The effect on the control coefficient of cytochrome ''c''ย oxidase (C''c''OX) over cell respiration of both the electrical (ฮฯ) and chemical (ฮpH) component of the mitochondrial transmembrane proton electrochemical gradient (ฮฮผH+) was investigated. The overall O<sub>2</sub> consumption and specific C''c''OX activity of actively phosphorylating cells were titrated with cyanide under conditions in which ฮฯ and ฮpH were selectively modulated by addition of ionophores. In the absence of ionophores, C''c''OX 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 ฮฯ is maximal, and in the presence of nigericin and valinomycin (CIV = 0.77), when ฮฮผH+ is abolished. In contrast, C''c''OX displayed a markedly lower control coefficient (CIV = 0.30) upon addition of valinomycin, when ฮฯ is converted into ฮpH. These results show that ฮฯ is responsible for the tight control of C''c''OX over respiration in actively phosphorylating cells. | |abstract=Metabolic control analysis was applied to intact HepG2 cells. The effect on the control coefficient of cytochrome ''c''ย oxidase (C''c''OX) over cell respiration of both the electrical (ฮฯ) and chemical (ฮpH) component of the mitochondrial transmembrane proton electrochemical gradient (ฮฮผH+) was investigated. The overall O<sub>2</sub> consumption and specific C''c''OX activity of actively phosphorylating cells were titrated with cyanide under conditions in which ฮฯ and ฮpH were selectively modulated by addition of ionophores. In the absence of ionophores, C''c''OX 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 ฮฯ is maximal, and in the presence of nigericin and valinomycin (CIV = 0.77), when ฮฮผH+ is abolished. In contrast, C''c''OX displayed a markedly lower control coefficient (CIV = 0.30) upon addition of valinomycin, when ฮฯ is converted into ฮpH. These results show that ฮฯ is responsible for the tight control of C''c''OX over respiration in actively phosphorylating cells. | ||
|keywords=Nigericin, Valinomycin, Cytochrome C oxidase,ย Membrane potential | |keywords=Nigericin, Valinomycin, Cytochrome C oxidase,ย Membrane potential | ||
}} | }} | ||
{{Labeling | {{Labeling | ||
|organism=Rat | |instruments=Oxygraph-2k | ||
|organism=Human, Rat | |||
|tissues=Hepatocyte; Liver | |tissues=Hepatocyte; Liver | ||
|enzymes=Complex IV; Cytochrome c Oxidase | |preparations=Intact Cell; Cultured; Primary | ||
|topics= | |enzymes=Complex IV; Cytochrome c Oxidase | ||
|topics=Flux Control; Additivity; Threshold; Excess Capacity, Coupling; Membrane Potential | |||
}} | }} |
Revision as of 09:31, 8 September 2011
Dalmonte ME, Forte E, Genova ML, Giuffrรจ A, Sarti P, Lenaz G (2009) Control of respiration by cytochrome c oxidase in intact cells: role of the membrane potential. J. Biol. Chem. 284(47):32331-5. |
Dalmonte ME, Forte E, Genova ML, Giuffre A, Sarti P, Lenaz G (2009) J. Biol. Chem.
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 (ฮฯ) and chemical (ฮpH) component of the mitochondrial transmembrane proton electrochemical gradient (ฮฮผH+) was investigated. The overall O2 consumption and specific CcOX activity of actively phosphorylating cells were titrated with cyanide under conditions in which ฮฯ and ฮpH 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 ฮฯ is maximal, and in the presence of nigericin and valinomycin (CIV = 0.77), when ฮฮผH+ is abolished. In contrast, CcOX displayed a markedly lower control coefficient (CIV = 0.30) upon addition of valinomycin, when ฮฯ is converted into ฮpH. These results show that ฮฯ is responsible for the tight control of CcOX over respiration in actively phosphorylating cells. โข Keywords: Nigericin, Valinomycin, Cytochrome C oxidase, Membrane potential
Labels:
Organism: Human, Rat
Tissue;cell: Hepatocyte; Liver"Hepatocyte; Liver" is not in the list (Heart, Skeletal muscle, Nervous system, Liver, Kidney, Lung;gill, Islet cell;pancreas;thymus, Endothelial;epithelial;mesothelial cell, Blood cells, Fat, ...) of allowed values for the "Tissue and cell" property.
Preparation: Intact Cell; Cultured; Primary"Intact Cell; Cultured; Primary" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property.
Enzyme: Complex IV; Cytochrome c Oxidase"Complex IV; Cytochrome c Oxidase" is not in the list (Adenine nucleotide translocase, Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Inner mt-membrane transporter, Marker enzyme, Supercomplex, TCA cycle and matrix dehydrogenases, ...) of allowed values for the "Enzyme" property.
Regulation: Flux Control; Additivity; Threshold; Excess Capacity"Flux Control; Additivity; Threshold; Excess Capacity" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property., Coupling; Membrane Potential"Coupling; Membrane Potential" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property.
HRR: Oxygraph-2k