Synthesis of Adenosine Triphosphate by a Protonmotive Force in Rat Liver Mitochondria

Nature ◽  
1966 ◽  
Vol 212 (5059) ◽  
pp. 257-258 ◽  
Author(s):  
R. A. REID ◽  
JENNIFER MOYLE ◽  
PETER MITCHELL
Keyword(s):  
Adenosine Triphosphate ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Protonmotive Force

scholarly journals Oxygen-pulse curves in rat liver mitochondrial suspensions. Some observations and deductions

1979 ◽  
Vol 180 (1) ◽  
pp. 161-174 ◽  
Author(s):  
G P Archbold ◽  
C L Farrington ◽  
S A Lappin ◽  
A M McKay ◽  
F H Malpress
Keyword(s):  
Rat Liver ◽  
Atp Synthesis ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Protonmotive Force ◽  
Mitochondrial Inner Membrane ◽  
Fixed Charges ◽  
Charge Concentration ◽  
C 50 ◽  
Proton Movement

1. The inference, implicit in the chemiosmotic hypothesis, that protons move into the bulk phase during ATP synthesis was investigated. 2. Incubation of rat liver mitochondria in the presence of the cation exchanger CM-Sephadex C-50 caused alkalinization in the medium, though total ATP synthesis remained unchanged. The addition of N-ethylmaleimide prevented the alkalinization, but there was still no indication of protons passing into the medium. The expected proton movement [Mitchell & Moyle (1967) Biochem. J. 105, 1147–1162] was readily detected when as an equivalent acid pulse. 3. Analysis of delta H+ decay curves after O2 pulses (3 micrograms-atoms of O/g of protein) indicated the presence of fast and slow components of decay, with first-order rate constants (k) of 0.24s-1 and 0.032s-1. The fast decay was finite and was eliminated in the presence of N-ethylmaleimide. 4. These observations are interpreted as evidence for the development of unmasking of fixed charges on the outer surface of the mitochondrial inner membrane during energization and for the existence of proton-retentive electrical fields (rho-zones) on this surface. The charge concentration is calculated as about 1 charge/10nm2. 5. A cycle of changes in a single fixed-charge molecule is proposed which mediates both Ca2+ uptake and the first step in the utilization of the rho-zone protonmotive force, delta p rho.

Kinetics and control of oxidative phosphorylation in rat liver mitochondria after chronic ethanol feeding

2000 ◽  
Vol 349 (2) ◽  
pp. 519-526 ◽  
Author(s):  
Ausra MARCINKEVICIUTE ◽  
Vida MILDAZIENE ◽  
Sara CRUMM ◽  
Oleg DEMIN ◽  
Jan B. HOEK ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Proton Leak ◽  
Rat Liver Mitochondria ◽  
Protonmotive Force ◽  
Compensatory Mechanisms ◽  
Mitochondrial Energy Metabolism ◽  
Ethanol Feeding ◽  
And Control

Changes in the kinetics and regulation of oxidative phosphorylation were characterized in isolated rat liver mitochondria after 2 months of ethanol consumption. Mitochondrial energy metabolism was conceptually divided into three groups of reactions, either producing protonmotive force (∆p) (the respiratory subsystem) or consuming it (the phosphorylation subsystem and the proton leak). Manifestation of ethanol-induced mitochondrial malfunctioning of the respiratory subsystem was observed with various substrates; the respiration rate in State 3 was inhibited by 27±4% with succinate plus amytal, by 20±4% with glutamate plus malate, and by 17±2% with N,N,Nʹ,Nʹ-tetramethyl-p-phenylenediamine/ascorbate. The inhibition of the respiratory activity correlated with the lower activities of cytochrome c oxidase, the bc1 complex, and the ATP synthase in mitochondria of ethanol-fed rats. The block of reactions consuming the ∆p to produce ATP (the phosphorylating subsystem) was suppressed after 2 months of ethanol feeding, whereas the mitochondrial proton leak was not affected. The contributions of ∆p supply (the respiratory subsystem) and ∆p demand (the phosphorylation and the proton leak) to the control of the respiratory flux were quantified as the control coefficients of these subsystems. In State 3, the distribution of control exerted by different reaction blocks over respiratory flux was not significantly affected by ethanol diet, despite the marked changes in the kinetics of individual functional units of mitochondrial oxidative phosphorylation. This suggests the operation of compensatory mechanisms, when control redistributes among the different components within the same subsystem.

scholarly journals The relationship between the rate of respiration and the protonmotive force. The role of proton conductivity

1984 ◽  
Vol 219 (2) ◽  
pp. 401-404 ◽  
Author(s):  
P S O'Shea ◽  
J B Chappell
Keyword(s):  
Proton Conductivity ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Protonmotive Force ◽  
Specific Rate ◽  
Chemiosmotic Hypothesis ◽  
The Relationship

It is shown by titrating a suspension of rat liver mitochondria with either ADP or an uncoupler that a specific rate of respiration may not have a unique associated value of the protonmotive force. Alternatively, a specific protonmotive force may not be associated with a unique rate of respiration. It seems that the rate of respiration and the protonmotive force are more sensitive to the agents used for the titrations than to each other. Such observations are not easily explained by the chemiosmotic hypothesis. It is, however, possible provided that the proton conductivities, i.e. the rates of dissipation of the protonmotive force, are considered to be different for each of the agents used to titrate the rate of respiration at the same protonmotive force, or vice versa.

scholarly journals Sub-mitochondrial location of Ruthenium Red-sensitive calcium-ion transport and evidence for its enrichment in a specific population of rat liver mitochondria

1978 ◽  
Vol 174 (3) ◽  
pp. 1011-1019 ◽  
Author(s):  
Fyfe L. Bygrave ◽  
Thomas P. Heaney ◽  
Chidambaram Ramachandran
Keyword(s):  
Rat Liver ◽  
Liver Homogenate ◽  
Liver Mitochondria ◽  
Ruthenium Red ◽  
Rat Liver Mitochondria ◽  
Protonmotive Force ◽  
Glycerophosphate Dehydrogenase ◽  
Biogenesis Of Mitochondria ◽  
The Individual ◽  
Calcium Ion Transport

1. Seven fractions sedimenting at between 3000 and 120000g-min were prepared from a rat liver homogenate by differential centrifugation in buffered iso-osmotic sucrose. The following measurements were carried out on each of these fractions: Ruthenium Red-sensitive Ca2+ transport in the absence and in the presence of Pi as well as in the presence of N-ethylmaleimide to prevent Pi cycling, succinate-supported respiration in the absence and in the presence of ADP, the ΔE and −59 ΔpH components of the protonmotive force, cytochrome oxidase, uncoupler-stimulated adenosine triphosphatase, α-glycerophosphate dehydrogenase, Pi content and the effect on the ‘resting’ rate of respiration of repeated additions of a fixed Ca2+ concentration. 2. Ca2+ transport either in the presence or in the absence of added Pi and in the presence of N-ethylmaleimide exhibits significantly higher rates in the fraction sedimenting at 8000g-min. By contrast, respiration in the presence or in the absence of added ADP and the values for ΔE and −59 ΔpH were similar in those fractions sedimenting between 4000 and 20000g-min, indicating that the driving force for Ca2+ transport was similar in each of these fractions. 3. Experiments designed to determine the capacity of the individual fractions for Ca2+, as measured by the effect of repeated additions of Ca2+ on the resting rate of respiration, showed that fraction 2, i.e. that sedimenting at 8000g-min, also exhibited the greatest tolerance towards the uncoupling action of the ion. 4. Of the three enzyme activity profiles, only that of α-glycerophosphate dehydrogenase was similar to that of Ca2+ transport. Because previous workers have assigned this enzyme to loci in the inner peripheral membrane [Werner & Neupert (1972) Eur. J. Biochem.25, 379–396], it is concluded that the Ruthenium Red-sensitive Ca2+- transport system also is located in this domain of the inner membrane. The relation of these findings to the mechanisms of mitochondrial Ca2+ transport and the biogenesis of mitochondria is discussed.

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