Lanthanide‐sensitive calcium—monocarboxylate symport in rat liver mitochondria

Moyle, Jennifer; Mitchell, Peter

doi:10.1016/0014-5793(77)81073-9

Cited by 30 publications

(14 citation statements)

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“…Thus the role of the ionophore present in cytochrome oxidase preparations remains obscure. The curious stimulation of Ca2+ transport in COV by valinomycin suggests a complex mechanism perhaps involving transport of an anion [2,20].…”

Section: Discussionmentioning

confidence: 99%

“…Despite some controversy concerning the mechanism of Ca2+ uptake into mitochondria [ 1,2], it is generally agreed that the process is electrophoretic, driven by the respiratory activity of the inner mitochondrial membrane. A small polypeptide fulfilling the requirements of an ionophore has been isolated from calf heart mitochondria and it reportedly participates in the electrophoretic, ruthenium-red sensitive uptake of Ca2' [3].…”

Section: Introductionmentioning

confidence: 99%

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Calcium uptake by reconstituted vesicles is mediated by a chymotrypsin‐sensitive peptide associated with cytochrome oxidase

1980

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calcium uptake by reconstituted vesicles is mediated by a chymotrypsin‐sensitive peptide associated with cytochrome oxidase

1980

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“…Butyrate, therefore, should be at least as effective as 3-hydroxybutyrate in collapsing ApH, releasing the respiratory control, and allowing further Sr2+ import, but this was not observed. Moyle and Mitchell [9] were able to explain these results in terms of a specific uptake system by saying first, that in the presence of NEM (to prevent phosphate cycling) SrZ + was imported along with leaked endogenous phosphate on an electrogenic Ca2 ' (Sr2 ')-phosphate symporter ; and second, that when the endogenous phosphate was exhausted, further Sr2+ import could occur only if 3-hydroxybutyrate (or any other substrate for the putative Ca2 ' (Sr'+)-rnonocarboxylate symporter) was added.…”

Section: Inhibition Of 3-hydroxybutyrate Oxidase Activity By Nemmentioning

confidence: 99%

“…' SrZ+ was used in most of the experiments in [9] and in all of the experiments in this paper because Ca2 b) A larger quantity of Sr2+ was imported on addition of 3-hydroxybutyrate to mitochondria in state 6 than on addition of the other anions.…”

Section: Inhibition Of 3-hydroxybutyrate Oxidase Activity By Nemmentioning

confidence: 99%

“…3-Hydroxybutyrate is a respiratory substrate, making it unique among the anions tested in [9] which permeate the inner mitochondrial membrane as free acid. However, the possibility that the peculiar effects of 3-hydroxybutyrate were somehow dependent on its being a respiratory substrate was rejected.…”

Section: Inhibition Of 3-hydroxybutyrate Oxidase Activity By Nemmentioning

confidence: 99%

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Is there Ca2+(Sr2+)-3-hydroxybutyrate symport in rat-liver mitochondria?. A reappraisal

Moody¹,

West²,

Mitchell³

et al. 1986

Eur J Biochem

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The observation in this laboratory that respiration and Sr2+ import were stimulated by the addition of 3-hydroxybutyrate to suspensions of N-ethylmaleimide-treated mitochondria respiring in state 6, after the addition of Sr2+, in a sucrose medium containing choline as substrate, led to the proposal by FEBS Lett. 84, 135-1401 that there is a Ca2+(Sr2+)-3-hydroxybutyrate sylnporter in rat liver mitochondria.However, experiments described in the present paper support a different interpretation. Under the conditions of the experiments by Moyle and Mitchell, the rate of respiration and the poise of Sr2+ accumulation are mainly limited, not by A&,+, but by lack of respiratory substrate. Even though N-ethylmaleimide is a potent inhibitor of 3-hydroxybutyrate dehydrogenase, we have found that, somewhat surprisingly, under the special conditions of these experiments, sufficient 3-hydroxybutyrate dehydrogenase activity remains available to account for the 3-hydroxybutyrate-dependent respiratory stimulation and Sr2 ' import.The view held generally is that Ca2+ import by respiring rat liver mitochondria occurs electrophoretically via a uniporter specific for the divalent cations Ca2+, SrZ+, Mn2+ and Ba2+ [l]. Physiological Ca2+ export (as opposed to efflux caused by the lytic action of high [Ca"] [2]) is thought to occur by an electroneutral 2H+/CaZ + exchange system that has relatively low activity compared to the uniporter [3] and is inhibited by Sr2+ [4] (for a recent review see [S]). Therefore, the distribution of Ca2 + across the inner mitochondrial membrane does not achieve thermodynamic equilibrium during in vitro experiments. Instead, a steady state is reached in which CaZ' cycles between the medium and the matrix, and the concentration of unbound Ca2 + outside the mitochondria ([Ca2 ' 1;) is approximately micromolar. If the [Ca2+]6 is raised above this level, the rate of import rises above the rate of export, and net import occurs. As a result, the [Ca2']\ falls and, hence, the rate of import falls until a new steady state is reached [5].In 1977 Moyle and Mitchell [6] questioned whether net import of Ca2+ (or Sr2+) by respiring mitochondria involved a Ca2+-uniporter. They measured the +H+ (acid)/+Ca ratio during net import of Ca2+ by respiring mitochondria, either by adding a pulse of oxygen to an anaerobic mitochondrial suspension, or by adding CaZ+ to an aerobic mitochondrial suspension in state 4. In the presence of N-ethylmaleimide (NEM; to prevent electroneutral symport of H + with phosphate on the phosphoric acid porter [7]) this ratio was

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David Keilins Konzept der Atmungskette und dessen chemiosmotische Konsequenzen (Nobel‐Vortrag)

Mitchell

1979

Angewandte Chemie

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nisch moglich ist, ist unbestritten. In Hinblick auf die Herabsetzung der NO-Emission aus Kraftwerken sei auf die Wirbelschicht-oder F l i e R b e t t -V e r b r e n n~n g~~~] verwiesen, die wegen der weitaus besseren Warmeiibertragung bei niedrigeren Temperaturen arbeiten kann und damit zu wesentlich geringerer NO-Bildung fuhrt. Die Grundlagen dieses Verfahrens wurden vor mehr als 50 Jahren bei der BASF entwickelt; das Verfahren hat aber, abgesehen von seiner technischen Ausarbeitung in Pilotanlagen, noch keinen Eingang in konventionelle Kraftwerke gefunden. Ein weiteres, erst kurzlich von der EXXON patentiertes Verfahren zur Verringerung der NO-Emission in Verbrennungsanlagen ist der Zusatz von lVH3/Oz-Gemischen~"1. Hierbei beruht die NOVerminderuing auf der schnellen homogenen Gasreaktion [lo] R .Jaenirkic. Ber Bunxnges. Phys. Cheni. X2. I19X (1978).

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Lanthanide‐sensitive calcium—monocarboxylate symport in rat liver mitochondria

Cited by 30 publications

References 10 publications

Calcium uptake by reconstituted vesicles is mediated by a chymotrypsin‐sensitive peptide associated with cytochrome oxidase

Calcium uptake by reconstituted vesicles is mediated by a chymotrypsin‐sensitive peptide associated with cytochrome oxidase

Is there Ca2+(Sr2+)-3-hydroxybutyrate symport in rat-liver mitochondria?. A reappraisal

David Keilins Konzept der Atmungskette und dessen chemiosmotische Konsequenzen (Nobel‐Vortrag)

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