Brand, M D, Reynafarje, B, Lehninger, A L
The number of protons ejected during electron transport per pair of electrons per energy-conserving site (the H+/site ratio) was measured in rat liver mitochondria by three different methods under...
H+/ATP ratio during ATP hydrolysis by mitochondria: modification of the chemiosmotic theory.
The stoichiometry of H+ ejection by mitochondria during hydrolysis of a small pulse of ATP (the H+/ATP ratio) has been reexamined in the light of our recent observation that the stoichiometry of H+...
Brand, M D, Harper, M E, Taylor, H C
The control exerted by substrate oxidation reactions, by ATP turnover and by the proton leak over the oxygen consumption rate, the phosphorylation rate, the proton leak rate and the protonmotive...
Quant, P A, Tubbs, P K, Brand, M D
1. The activity of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase (EC 4.1.3.5) in extracts of rapidly frozen rat livers was doubled in animals treated in various ways to increase ketogenic flux....
Thyroid-hormone control of state-3 respiration in isolated rat liver mitochondria.
Hafner, R P, Brown, G C, Brand, M D
Oxidative phosphorylation can be treated as two groups of reactions; those that generate protonmotive force (dicarboxylate carrier, succinate dehydrogenase and the respiratory chain) and those that...
Brand, M D, Hafner, R P, Brown, G C
We measured the relationship between rate of respiration and membrane potential in isolated mitochondria titrated with malonate (to inhibit the electron transport chain) or with uncoupler (to...
Stimulation of respiration by mitogens in rat thymocytes is independent of mitochondrial calcium.
The role of calcium in the control of respiration by the mitogen concanavalin A (ConA) was investigated in rat thymocytes. ConA induced an increase in both mitochondrial respiration and the...
1. In the presence of physiological concentrations of Na+ and Mg2+, the rate of citrulline synthesis by isolated rat liver mitochondria respiring on a range of substrates was stimulated by up to 60%...
In this paper we examine the non-linearity of the relationship between the proton electrochemical gradient across the mitochondrial inner membrane (delta p) and oxygen consumption of...
A hierarchy of ATP-consuming processes in mammalian cells.
The rates of different ATP-consuming reactions were measured in concanavalin A-stimulated thymocytes, a model system in which more than 80% of the ATP consumption can be accounted for. There was a...
Brand, M D, Chien, L F, Diolez, P
By measuring the relationship between protonmotive force and the increment in oxygen consumption by mitochondria treated with submaximal amounts of uncoupler, we have experimentally tested four...
TMB-8 inhibited respiration of rat thymocytes and rat liver mitochondria, probably by inhibition of NADH dehydrogenase. TMB-8 markedly decreased both the cellular ATP concentration and the...
Thermodynamic control of electron flux through mitochondrial cytochrome bc1 complex.
The redox states of exogenously added ubiquinone-2 and cytochrome c, and the protonmotive force (delta p) of rat liver mitochondria were measured as the respiration rate was titrated with the...
Brand, M D, Al-Shawi, M K, Brown, G C, Price, B D
Steady-state kinetic measurements showed that NN'-dicyclohexylcarbodi-imide decreased the observed H+/2e ratio of H+ transport by mitochondria respiring on succinate, acting mainly at the cytochrome...
Electroneutral efflux of Ca2+ from liver mitochondria.
Respiring liver mitochondria were allowed to export Ca2+ on the endogenous Ca2+/nH+ antiporter in the presence of Ruthenium Red (to inhibit uptake on the Ca2+ uniporter) until a steady state was...
The stoichiometry of the exchange catalysed by the mitochondrial calcium/sodium antiporter.
Rat heart mitochondria respiring on succinate in the presence of Ruthenium Red (to inhibit uptake on the Ca2+ uniporter) released Ca2+ on the calcium/sodium antiporter until a steady state was...
We have confirmed that the respiration rate of rat liver mitochondria can be substantially inhibited with only a small drop in proton motive force. We have directly measured the passive proton...
The control of electron flux through cytochrome oxidase.
1. The electron flux through cytochrome oxidase is a linear function of the net thermodynamic force across the complex over a limited range of conditions. 2. Over a wide range of conditions the...
1. The respiration rate of rat liver mitochondria was stimulated by up to 70% when the extramitochondrial Ca2+ concentration was raised from 103 to 820 nM. This occurred when pyruvate,...
Exchangeable calcium pools were measured in rat thymocytes by 45Ca labelling and selective depletion of intracellular pools with oligomycin in the presence or absence of rotenone. The mitochondrial...
Hypothyroidism in rats does not lower mitochondrial ADP/O and H+/O ratios.
We investigated reports that mitochondria isolated from hypothyroid rats have decreased ADP/O and H+/O ratios. We observed no decrease in the H+/O ratio in mitochondria from hypothyroid rats, in the...
The thermodynamic forces on electrons (delta Eh) and protons (delta p) across mitochondrial complexes I, III and IV were measured in isolated mitochondria respiring on succinate. The force ratio...
The rate of phosphorylation of ADP by isolated mitochondria respiring on succinate was set by addition of ATP, ADP or ADP plus malonate. We measured the rates of phosphorylation and respiration and...
Brand, M D, Couture, P, Else, P L, Withers, K W, Hulbert, A J
Standard metabolic rate is 7-fold greater in the rat (a typical mammal) than in the bearded dragon, Amphibolurus vitticeps (a reptile with the same body mass and temperature). Rat hepatocytes respire...
Mechanism of activation of pyruvate dehydrogenase by mitogens in pig lymphocytes.
Baumgarten, E, Brand, M D, Pozzan, T
The activity of pyruvate dehydrogenase in extracts of pig mesenteric lymphocytes was measured under different preincubation conditions. The mitogens concanavalin A and ionophore A23187 both increased...
Membrane potential of mitochondria in intact lymphocytes during early mitogenic stimulation.
The mitochondrial membrane potential (delta psi m) in intact lymphocytes was calculated by measuring the distribution of radiolabelled methyltriphenylphosphonium cation. The value obtained was 120...
Early plasma-membrane-potential changes during stimulation of lymphocytes by concanavalin A.
1. We have monitored the plasma-membrane potential of lymphocytes by measuring the accumulation of the lipophilic cation methyltriphenylphosphonium (TPMP+) in the presence of the uncoupler carbonyl...
1. The 3mV depolarization of pig lymphocytes observed within 2 1/2 min of treatment with concanavalin A [Felber & Brand (1983) Biochem. J. 210, 885-891] is dependent on the presence of high...
1. Addition of oxaloacetate or acetoacetate to isolated rat liver mitochondria results in an efflux of Ca2+. Concomitant with this efflux is an immediate oxidation of endogenous nicotinamide...
1. A method for the isolation of functionally intact mitochondria from lymphocytes is described. It involves digitonin breakage of the plasma membrane, followed by differential centrifugation. The...
Factors determining the plasma-membrane potential of lymphocytes.
1. Lymphocytes from pig mesenteric lymph node have low permeability to K+ (Rb+), Na+ and Cl-. None of these ions is in Nernst equilibrium with the plasma-membrane potential (delta psi p). 2. delta...
NN'-Dicyclohexylcarbodi-imide at low concentrations decreases the H+/2e ratio for rat liver mitochondria over the span succinate to oxygen from 5.9 +/- 0.3 (mean +/- S.E.M.) to 4.0 +/- 0.1 and for...
Ca2+ efflux from rat liver mitochondria can occur when endogenous nicotinamide nucleotides are oxidized. It is suggested that nicotinamide nucleotide induced by acetoacetate sensitizes the...
Davis, R J, Brand, M D, Martin, B R
1. A recently developed technique for the measurement of plasma-membrane and mitochondrial-membrane potentials in intact cells by using the distribution of 86Rb+ and [3H]methyltriphenylphosphonium+...
Steady-state H+/O stoichiometry of liver mitochondria.
We have measured the H+/O stoichiometry of rat liver mitochondria respiring in a steady-state, using a novel method. This involves measuring the initial rate of H+ back-flow into mitochondria after...
Glutamate and aspartate transport in rat brain mitochondria
1. Rat brain mitochondria did not swell in iso-osmotic solutions of ammonium or potassium (plus valinomycin) glutamate or aspartate, with or without addition of uncouplers. 2. Glutamate was able to...
Brand, M. D., Evans, Susan M., Mendes-Mourão, J., Chappell, J. B.
1. The effect of biologically synthesized and purified fluorocitrate on the metabolism of tricarboxylate anions by isolated rat liver mitochondria was investigated, in relation to the claim by Eanes...
The effect of chloroform on mitochondrial energy transduction.
The effect of chloroform on mitochondrial respiration with succinate was investigated by applying the method of Brand, Chien and Diolez [(1994) Biochem. J. 297, 27-29] to examine whether chloroform...
Methylprednisolone inhibits uptake of Ca2+ and Na+ ions into concanavalin A-stimulated thymocytes.
Buttgereit, F, Krauss, S, Brand, M D
The glucocorticoid drug methylprednisolone inhibits respiration in concanavalin A-stimulated rat thymocytes at concentrations that are relevant to its acute clinical efficacy against autoimmune...
Effect of 3,5-di-iodo-L-thyronine on the mitochondrial energy-transduction apparatus.
Lombardi, A, Lanni, A, Moreno, M, Brand, M D, Goglia, F
We examined the effect of a single injection of 3,5-di-iodo-L-thyronine (3,5-T2) (150 microg/100 g body weight) on the rat liver mitochondrial energy-transduction apparatus. We applied 'top-down'...
Effects of magnesium and nucleotides on the proton conductance of rat skeletal-muscle mitochondria.
During oxidative phosphorylation most of the protons pumped out to the cytosol across the mitochondrial inner membrane return to the matrix through the ATP synthase, driving ATP synthesis. However,...
AMP decreases the efficiency of skeletal-muscle mitochondria.
Cadenas, S, Buckingham, J A, St-Pierre, J, Dickinson, K, Jones, R B, Brand, M D
Mitochondrial proton leak in rat muscle is responsible for approx. 15% of the standard metabolic rate, so its modulation could be important in regulating metabolic efficiency. We report in the...
A mitochondrial uncoupling artifact can be caused by expression of uncoupling protein 1 in yeast.
Stuart, J A, Harper, J A, Brindle, K M, Jekabsons, M B, Brand, M D
Uncoupling protein 1 (UCP1) from mouse was expressed in yeast and the specific (GDP-inhibitable) and artifactual (GDP-insensitive) effects on mitochondrial uncoupling were assessed. UCP1 provides a...
Brand, M D, Reynafarje, B, Lehninger, A L
The number of protons ejected during electron transport per pair of electrons per energy-conserving site (the H+/site ratio) was measured in rat liver mitochondria by three different methods under...
H+/ATP ratio during ATP hydrolysis by mitochondria: modification of the chemiosmotic theory.
The stoichiometry of H+ ejection by mitochondria during hydrolysis of a small pulse of ATP (the H+/ATP ratio) has been reexamined in the light of our recent observation that the stoichiometry of H+...
Brand, M D, Harper, M E, Taylor, H C
The control exerted by substrate oxidation reactions, by ATP turnover and by the proton leak over the oxygen consumption rate, the phosphorylation rate, the proton leak rate and the protonmotive...
Quant, P A, Tubbs, P K, Brand, M D
1. The activity of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase (EC 4.1.3.5) in extracts of rapidly frozen rat livers was doubled in animals treated in various ways to increase ketogenic flux....
Thyroid-hormone control of state-3 respiration in isolated rat liver mitochondria.
Hafner, R P, Brown, G C, Brand, M D
Oxidative phosphorylation can be treated as two groups of reactions; those that generate protonmotive force (dicarboxylate carrier, succinate dehydrogenase and the respiratory chain) and those that...
Brand, M D, Hafner, R P, Brown, G C
We measured the relationship between rate of respiration and membrane potential in isolated mitochondria titrated with malonate (to inhibit the electron transport chain) or with uncoupler (to...
Stimulation of respiration by mitogens in rat thymocytes is independent of mitochondrial calcium.
The role of calcium in the control of respiration by the mitogen concanavalin A (ConA) was investigated in rat thymocytes. ConA induced an increase in both mitochondrial respiration and the...
1. In the presence of physiological concentrations of Na+ and Mg2+, the rate of citrulline synthesis by isolated rat liver mitochondria respiring on a range of substrates was stimulated by up to 60%...
In this paper we examine the non-linearity of the relationship between the proton electrochemical gradient across the mitochondrial inner membrane (delta p) and oxygen consumption of...
A hierarchy of ATP-consuming processes in mammalian cells.
The rates of different ATP-consuming reactions were measured in concanavalin A-stimulated thymocytes, a model system in which more than 80% of the ATP consumption can be accounted for. There was a...
Brand, M D, Chien, L F, Diolez, P
By measuring the relationship between protonmotive force and the increment in oxygen consumption by mitochondria treated with submaximal amounts of uncoupler, we have experimentally tested four...
TMB-8 inhibited respiration of rat thymocytes and rat liver mitochondria, probably by inhibition of NADH dehydrogenase. TMB-8 markedly decreased both the cellular ATP concentration and the...
Thermodynamic control of electron flux through mitochondrial cytochrome bc1 complex.
The redox states of exogenously added ubiquinone-2 and cytochrome c, and the protonmotive force (delta p) of rat liver mitochondria were measured as the respiration rate was titrated with the...
Brand, M D, Al-Shawi, M K, Brown, G C, Price, B D
Steady-state kinetic measurements showed that NN'-dicyclohexylcarbodi-imide decreased the observed H+/2e ratio of H+ transport by mitochondria respiring on succinate, acting mainly at the cytochrome...
Electroneutral efflux of Ca2+ from liver mitochondria.
Respiring liver mitochondria were allowed to export Ca2+ on the endogenous Ca2+/nH+ antiporter in the presence of Ruthenium Red (to inhibit uptake on the Ca2+ uniporter) until a steady state was...
The stoichiometry of the exchange catalysed by the mitochondrial calcium/sodium antiporter.
Rat heart mitochondria respiring on succinate in the presence of Ruthenium Red (to inhibit uptake on the Ca2+ uniporter) released Ca2+ on the calcium/sodium antiporter until a steady state was...
We have confirmed that the respiration rate of rat liver mitochondria can be substantially inhibited with only a small drop in proton motive force. We have directly measured the passive proton...
The control of electron flux through cytochrome oxidase.
1. The electron flux through cytochrome oxidase is a linear function of the net thermodynamic force across the complex over a limited range of conditions. 2. Over a wide range of conditions the...
1. The respiration rate of rat liver mitochondria was stimulated by up to 70% when the extramitochondrial Ca2+ concentration was raised from 103 to 820 nM. This occurred when pyruvate,...
Exchangeable calcium pools were measured in rat thymocytes by 45Ca labelling and selective depletion of intracellular pools with oligomycin in the presence or absence of rotenone. The mitochondrial...
Hypothyroidism in rats does not lower mitochondrial ADP/O and H+/O ratios.
We investigated reports that mitochondria isolated from hypothyroid rats have decreased ADP/O and H+/O ratios. We observed no decrease in the H+/O ratio in mitochondria from hypothyroid rats, in the...
The thermodynamic forces on electrons (delta Eh) and protons (delta p) across mitochondrial complexes I, III and IV were measured in isolated mitochondria respiring on succinate. The force ratio...
The rate of phosphorylation of ADP by isolated mitochondria respiring on succinate was set by addition of ATP, ADP or ADP plus malonate. We measured the rates of phosphorylation and respiration and...
Brand, M D, Couture, P, Else, P L, Withers, K W, Hulbert, A J
Standard metabolic rate is 7-fold greater in the rat (a typical mammal) than in the bearded dragon, Amphibolurus vitticeps (a reptile with the same body mass and temperature). Rat hepatocytes respire...
Mechanism of activation of pyruvate dehydrogenase by mitogens in pig lymphocytes.
Baumgarten, E, Brand, M D, Pozzan, T
The activity of pyruvate dehydrogenase in extracts of pig mesenteric lymphocytes was measured under different preincubation conditions. The mitogens concanavalin A and ionophore A23187 both increased...
Membrane potential of mitochondria in intact lymphocytes during early mitogenic stimulation.
The mitochondrial membrane potential (delta psi m) in intact lymphocytes was calculated by measuring the distribution of radiolabelled methyltriphenylphosphonium cation. The value obtained was 120...
Early plasma-membrane-potential changes during stimulation of lymphocytes by concanavalin A.
1. We have monitored the plasma-membrane potential of lymphocytes by measuring the accumulation of the lipophilic cation methyltriphenylphosphonium (TPMP+) in the presence of the uncoupler carbonyl...
1. The 3mV depolarization of pig lymphocytes observed within 2 1/2 min of treatment with concanavalin A [Felber & Brand (1983) Biochem. J. 210, 885-891] is dependent on the presence of high...
1. Addition of oxaloacetate or acetoacetate to isolated rat liver mitochondria results in an efflux of Ca2+. Concomitant with this efflux is an immediate oxidation of endogenous nicotinamide...
1. A method for the isolation of functionally intact mitochondria from lymphocytes is described. It involves digitonin breakage of the plasma membrane, followed by differential centrifugation. The...
Factors determining the plasma-membrane potential of lymphocytes.
1. Lymphocytes from pig mesenteric lymph node have low permeability to K+ (Rb+), Na+ and Cl-. None of these ions is in Nernst equilibrium with the plasma-membrane potential (delta psi p). 2. delta...
NN'-Dicyclohexylcarbodi-imide at low concentrations decreases the H+/2e ratio for rat liver mitochondria over the span succinate to oxygen from 5.9 +/- 0.3 (mean +/- S.E.M.) to 4.0 +/- 0.1 and for...
Ca2+ efflux from rat liver mitochondria can occur when endogenous nicotinamide nucleotides are oxidized. It is suggested that nicotinamide nucleotide induced by acetoacetate sensitizes the...
Davis, R J, Brand, M D, Martin, B R
1. A recently developed technique for the measurement of plasma-membrane and mitochondrial-membrane potentials in intact cells by using the distribution of 86Rb+ and [3H]methyltriphenylphosphonium+...
Steady-state H+/O stoichiometry of liver mitochondria.
We have measured the H+/O stoichiometry of rat liver mitochondria respiring in a steady-state, using a novel method. This involves measuring the initial rate of H+ back-flow into mitochondria after...
Glutamate and aspartate transport in rat brain mitochondria
1. Rat brain mitochondria did not swell in iso-osmotic solutions of ammonium or potassium (plus valinomycin) glutamate or aspartate, with or without addition of uncouplers. 2. Glutamate was able to...
Brand, M. D., Evans, Susan M., Mendes-Mourão, J., Chappell, J. B.
1. The effect of biologically synthesized and purified fluorocitrate on the metabolism of tricarboxylate anions by isolated rat liver mitochondria was investigated, in relation to the claim by Eanes...
The effect of chloroform on mitochondrial energy transduction.
The effect of chloroform on mitochondrial respiration with succinate was investigated by applying the method of Brand, Chien and Diolez [(1994) Biochem. J. 297, 27-29] to examine whether chloroform...
Methylprednisolone inhibits uptake of Ca2+ and Na+ ions into concanavalin A-stimulated thymocytes.
Buttgereit, F, Krauss, S, Brand, M D
The glucocorticoid drug methylprednisolone inhibits respiration in concanavalin A-stimulated rat thymocytes at concentrations that are relevant to its acute clinical efficacy against autoimmune...
Effect of 3,5-di-iodo-L-thyronine on the mitochondrial energy-transduction apparatus.
Lombardi, A, Lanni, A, Moreno, M, Brand, M D, Goglia, F
We examined the effect of a single injection of 3,5-di-iodo-L-thyronine (3,5-T2) (150 microg/100 g body weight) on the rat liver mitochondrial energy-transduction apparatus. We applied 'top-down'...
Effects of magnesium and nucleotides on the proton conductance of rat skeletal-muscle mitochondria.
During oxidative phosphorylation most of the protons pumped out to the cytosol across the mitochondrial inner membrane return to the matrix through the ATP synthase, driving ATP synthesis. However,...
AMP decreases the efficiency of skeletal-muscle mitochondria.
Cadenas, S, Buckingham, J A, St-Pierre, J, Dickinson, K, Jones, R B, Brand, M D
Mitochondrial proton leak in rat muscle is responsible for approx. 15% of the standard metabolic rate, so its modulation could be important in regulating metabolic efficiency. We report in the...
A mitochondrial uncoupling artifact can be caused by expression of uncoupling protein 1 in yeast.
Stuart, J A, Harper, J A, Brindle, K M, Jekabsons, M B, Brand, M D
Uncoupling protein 1 (UCP1) from mouse was expressed in yeast and the specific (GDP-inhibitable) and artifactual (GDP-insensitive) effects on mitochondrial uncoupling were assessed. UCP1 provides a...