Proton electrochemical gradient and rate of controlled respiration in mitochondria

Gf, Azzone; Pozzan, Tullio; Massari, Stefano; Bragadin, Marcantonio

doi:10.1016/0005-2728(78)90035-x

Cited by 102 publications

(35 citation statements)

References 13 publications

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“…[lO,ll]) and rejected (e.g. [12,13]) without, however, conclusive experimental evidence being presented on either side. Since the centrifugation technique is commonly used, the point deserves attention on its own merits as well as within the context of flow-force correlations.…”

Section: Febs Lettersmentioning

confidence: 99%

Multiple relationships between rate of oxidative phosphorylation and Δµ̃H in rat liver mitochondria

Zoratti¹,

Petronilli²

1985

FEBS Letters

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Section: Febs Lettersmentioning

confidence: 99%

Multiple relationships between rate of oxidative phosphorylation and Δµ̃H in rat liver mitochondria

Zoratti¹,

Petronilli²

1985

FEBS Letters

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“…Thexe include direct interactions between ATP synthetase and components of the respiratory chain [14] such as cytochrome oxidase [15], titrations of the protonmotive force and phosphorylation in a variety of experimental conditions [16,17], and the enhanced depression by protonophorous uncoupling agents of the protonmotive force [18] or phosphorylation [19] in comparison with nigericin plus valinomycin in the presence of K'.…”

Section: Effect Of Energisation Upon Ihe Distribution Qf Tiimentioning

confidence: 99%

Uptake of Thallous Ions by Mitochondria is Stimulated by Nonactin but not by Respiration Alone

Skulskii¹,

Saris

Savina³

et al. 1981

Eur J Biochem

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Nonrespiring rat-liver mitochondria swell in media containing high concentrations of thallous nitrate, indicating passive penetration of Tl'. This swelling could be further stimulated by 10 nM or more nonactin while even 1 pM valinomycin was without effect. Nonactin was also much more potent than valinomycin in stimulating swelling of respiring mitochondria in the presence of thallous acetate. It is evident that nonactin acts as a potent ionophore of T1' able to promote both the passive and energized uptake of T1' in mitochondria.The distribution of TI+, present in trace concentrations below 1 mM, was measured during energisation by respiration both in the presence and absence of ionophores. Respiration induced net uptake of T1+ only in the presence of ionophores, though T1+ as a permeant cation was expected to sense respiration-induced changes in the membrane potential. The data may be interpreted as indicating that no transmembrane potential is formed upon energisation, but localized fields, which are able to interact with the lipophilic ionophore complexes of TI +, but not with the hydrophilic cation Tl'. This interpretation is valid only if thermodynamic equilibrium has been reached.

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“…We observed that in yeast mitochondria, as in rat liver mitochondria (60,61), there is more than one relationship between the respiratory rate and the size of 1p, when the respiratory rate is modi ed by either ADP plus Pi or by an uncoupler. Added ADP C Pi stimulates respiration more than uncoupler at the same 1p value.…”

Section: Modi Cations Of the Flow-force Relationships By External Atpmentioning

confidence: 93%

“…As pointed out previously (58), the key term which thermodynamically controls the respiratory rate is 2 £ 1E h ¡ n £ 1p, where 1E h is the span of redox potential between electron carriers over a segment or the entire respiratory chain that translocates n protons (and/or charges) upon the transfer of two electrons. Under the conditions where the redox span may be unchanged, the relationship between the respiratory ux and 1p is not unique and depends on the way in which the force varies (e.g., ATP synthesis stimulation, proton leak increase) (59)(60)(61). One of the proposed explanations is the possible allosteric link between the respiratory chain and ATP synthase (62,63), which leads to a change in the response of the oxygen uptake to 1p.…”

Section: Modi Cations Of the Flow-force Relationships By External Atpmentioning

confidence: 99%

Regulation of Cytochrome c Oxidase by Adenylic Nucleotides. Is Oxidative Phosphorylation Feedback Regulated by its End‐Products?

Beauvoit¹,

Rigoulet²

2001

IUBMB Life

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SummaryCytochrome c oxidase, which catalyzes an irreversible step of the respiratory chain, is one of the rate-controlling steps of oxidative phosphorylation on isolated mitochondria. The rate of electron transfer through the complex is primarily controlled by the associated thermodynamic forces, i.e., the span in redox potential between oxygen and cytochrome c and the protonmotive force. However, the electron ux also depends on the various kinetic effectors, including adenylic nucleotides. Although the number of binding sites for ATP and ADP on cytochrome oxidase is still a matter of debate, experiments performed on the solubilized and reconstituted enzyme provide strong functional evidence that the mammalian cytochrome c oxidase binds adenylic nucleotides on both sides of the inner membrane. These effects include modi cation in cytochrome c af nity, allosteric inhibition and changes in proton pumping ef ciency. Immunological studies have pointed out the role of subunit IV and that of an ATP-binding protein, subunit VIa, in these kinetic regulations. In yeast, the role of the nuclear-encoded subunits in assembly and regulation of the cytochrome c oxidase has been further substantiated by using gene-disruption analysis. Using a subunit VIa-null mutant, the consequences of the ATP regulation on oxidative phosphorylation have been further investigated on isolated mitochondria. Taken together, the data demonstrate that there are multiple regulating sites for ATP on the yeast cytochrome oxidase with respect to the location (matrix versus cytosolic side), kinetic effect (activation versus inhibition) and consequence on the ow-force relationships. The question is therefore raised as to the

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Proton electrochemical gradient and rate of controlled respiration in mitochondria

Cited by 102 publications

References 13 publications

Multiple relationships between rate of oxidative phosphorylation and Δµ̃H in rat liver mitochondria

Multiple relationships between rate of oxidative phosphorylation and Δµ̃H in rat liver mitochondria

Uptake of Thallous Ions by Mitochondria is Stimulated by Nonactin but not by Respiration Alone

Regulation of Cytochrome c Oxidase by Adenylic Nucleotides. Is Oxidative Phosphorylation Feedback Regulated by its End‐Products?

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