Acid–base titration across the membrane system of rat-liver mitochondria: Catalysis by uncouplers
Peter Mitchell,Jennifer Moyle +1 more
TLDR
Pulsed acid-base titrations of suspensions of rat-liver mitochondria under anaerobic equilibrium conditions show fast and slow titration processes that will account quantitatively for the observed respiratory control in state 4, assuming that oxidoreduction and phosphorylation are coupled by a circulating proton current as required by the chemi-osmotic hypothesis.Abstract:
1. Pulsed acid-base titrations of suspensions of rat-liver mitochondria under anaerobic equilibrium conditions show fast and slow titration processes. 2. The fast process is the titration of the outer aqueous phase of the mitochondria, which is continuous with the suspension medium, and the slow process can be identified with the titration of the inner aqueous phase of the mitochondria, which is separated from the outer aqueous phase by the non-aqueous osmotic barrier or M phase of the cristae membrane system. 3. The buffering power of the outer and inner phases have been separately measured over a range of pH values. 4. The rate of titration of the inner aqueous phase under a known protonmotive force across the M phase has been characterized by an effective proton conductance coefficient, which, near pH7 and at 25 degrees , is only 0.45mumho/cm.(2) of the M-phase membrane. 5. The low effective proton conductance of the M phase will account quantitatively for the observed respiratory control in state 4, assuming that oxidoreduction and phosphorylation are coupled by a circulating proton current as required by the chemi-osmotic hypothesis. 6. The addition of 2,4-dinitrophenol (or carbonyl cyanide p-trifluoromethoxyphenylhydrazone) at normal uncoupling concentrations causes a large increase in the effective proton conductance of the M phase of the cristae membrane. 7. The increase of the effective proton conductance of the M phase by 2,4-dinitrophenol (or carbonyl cyanide p-trifluoromethoxyphenylhydrazone) will account quantitatively for the short-circuiting effect of the uncoupling agent on the proton current and for the observed rise of the rate of respiration to that characteristic of state 3 or higher.read more
Citations
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Energetics of bacterial growth: balance of anabolic and catabolic reactions.
J B Russell,Gregory M. Cook +1 more
TL;DR: Recent work indicated that bacteria can also use futile cycles of potassium, ammonia, and protons through the cell membrane to dissipate ATP either directly or indirectly, and the utility of energy spilling in bacteria has been a curiosity.
Journal ArticleDOI
The Influence of Respiration and ATP Hydrolysis on the Proton‐Electrochemical Gradient across the Inner Membrane of Rat‐Liver Mitochondria as Determined by Ion Distribution
TL;DR: The extra-mitochondrial phosphate potential sustainable by respiration was found to change in parallel to Δp, but to exceed the latter parameter when based upon a stoichiometry of two protons translocated per ATP synthesised.
Journal ArticleDOI
Cardiolipins and biomembrane function
TL;DR: Evidence is discussed for roles of cardiolipins in oxidative phosphorylation mechanisms that regulate State 4 respiration by returning ejected protons across and over bacterial and mitochondrial membrane phospholipids, and that regulates State 3 respiration through the relative contributions of proteins that transport protons, electrons and/or metabolites.
Journal ArticleDOI
Estimation of membrane potential and pH difference across the cristae membrane of rat liver mitochondria.
P. Mitchell,J. Moyle +1 more
TL;DR: The effects of changing Δp in mitochondrial suspensions in State 4 with uncoupling agent and with pulses of acid, alkali, calcium salt and ADP have been found to be in accord with the chemiosmotic hypothesis.
Journal ArticleDOI
Conservation and transformation of energy by bacterial membranes.
TL;DR: Energy Transductions in Mitochondria and the Role of the Membrane in Motility, Bacteriocins and the Energized State are studied.
References
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Journal ArticleDOI
Coupling of Phosphorylation to Electron and Hydrogen Transfer by a Chemi-Osmotic type of Mechanism
TL;DR: Coupling of Phosphorylation to Electron and Hydrogen Transfer by a Chemi-Osmotic type of Mechanism is described.
Journal ArticleDOI
A micro-biuret method for estimating proteins.
Ruth F. Itzhaki,D.M. Gill +1 more
TL;DR: Measurements on several dipeptides showed that proline peptide do not form ultraviolet-absorbing complexes with copper whereas prolyl peptides do form such complexes, which explains the finding that gelatin (which has a high proportion of proline and of hydroxyproline residues) is less reactive with copper than are the other proteins studied here.
Journal ArticleDOI
ULTRASTRUCTURAL BASES FOR METABOLICALLY LINKED MECHANICAL ACTIVITY IN MITOCHONDRIA I. Reversible Ultrastructural Changes with Change in Metabolic Steady State in Isolated Liver Mitochondria
TL;DR: Isolated mitochondria were found to oscillate between the orthodox and condensed conformations during reversible transitions between State III and State IV, representing an ultrastructural basis for metabolically linked mechanical activity in tightly coupled mitochondria.
Journal ArticleDOI
Water uptake and extrusion by mitochondria in relation to oxidative phosphorylation.
Journal ArticleDOI
Chemiosmotic coupling in oxidative and photosynthetic phosphorylation
TL;DR: This remarkable account of Peter Mitchell's ideas originally published in 1966 is a landmark and must-read publication for any scientist in the field of bioenergetics.
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