Vasington 1962 J Biol Chem: Difference between revisions
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{{Publication | {{Publication | ||
|title=Vasington FD, Murphy JV (1962) Ca++ uptake by rat kidney mitochondria and its dependence on respiration and phosphorylation. J Biol Chem 237: 2670- | |title=Vasington FD, Murphy JV (1962) Ca<sup>++</sup> uptake by rat kidney mitochondria and its dependence on respiration and phosphorylation. J Biol Chem 237:2670-7. | ||
|info=[http://www.jbc.org/content/237/8/2670.full.pdf+html | |info=[http://www.ncbi.nlm.nih.gov/pubmed/13925019?dopt=Abstract PMID: 13925019 Open Access]; [http://www.jbc.org/content/237/8/2670.full.pdf+html PDF] | ||
|authors=Vasington FD, Murphy JV | |authors=Vasington FD, Murphy JV | ||
|year=1962 | |year=1962 | ||
|journal=J Biol Chem | |journal=J Biol Chem | ||
|abstract=RatĀ kidneyĀ mitochondriaĀ bindĀ largeĀ quantitiesĀ ofĀ Ca<sup>++</sup>.Ā MaximalĀ Ca<sup>++</sup>Ā bindingĀ requiresĀ theĀ presenceĀ o fĀ aĀ respiratory substrateĀ suchĀ asĀ isocitrateĀ orĀ succinate,Ā asĀ wellĀ asĀ adenosine triphosphateĀ (ATP),Ā inorganicĀ orthophosphateĀ (Pi),Ā andĀ Mg<sup>++</sup>. NoĀ Ca<sup>++</sup>Ā isĀ boundĀ inĀ theĀ absenceĀ ofĀ ATP,Ā whereasĀ ifĀ PiĀ orĀ Mg<sup>++</sup> isĀ omitted,Ā theĀ amountĀ ofĀ Ca<sup>++</sup>Ā boundĀ isĀ decreasedĀ 40Ā toĀ 70%. AdenosineĀ diphosphateĀ (ADP)Ā canĀ substituteĀ partiallyĀ forĀ ATP, presumablyĀ throughĀ formationĀ ofĀ ATPĀ byĀ adenylateĀ kinase,Ā but otherĀ nucleosideĀ di-Ā andĀ triphosphatesĀ testedĀ areĀ essentiallyĀ inactive. | |||
RespiratoryĀ inhibitorsĀ suchĀ asĀ Amytal,Ā antimycinĀ A,Ā cyanide, andĀ azideĀ inhibitĀ Ca<sup>++</sup>Ā binding,Ā asĀ doĀ uncouplingĀ agentsĀ suchĀ as dinitrophenol,Ā dicoumarol,Ā andĀ gramicidin.Ā Significantly,Ā Ca<sup>++</sup> isĀ boundĀ byĀ mitochondriaĀ evenĀ inĀ theĀ presenceĀ ofĀ uncoupling quantitiesĀ ofĀ Ca<sup>++</sup>.Ā DinitrophenolĀ andĀ otherĀ uncouplingĀ agents thereforeĀ blockĀ Ca<sup>++</sup> bindingĀ underĀ conditionsĀ inĀ whichĀ phosphorylationĀ isĀ alreadyĀ uncoupledĀ byĀ Ca<sup>++</sup>. | |||
EndogenousĀ Ca<sup>++</sup>Ā isĀ releasedĀ fromĀ mitochondriaĀ incubatedĀ in theĀ absenceĀ ofĀ ATPĀ orĀ ADPĀ orĀ inĀ theĀ presenceĀ ofĀ antimycinĀ A, dinitrophenol,Ā orĀ HgC12,Ā suggestingĀ thatĀ similarĀ factorsĀ influence theĀ retentionĀ ofĀ endogenousĀ Ca<sup>++</sup>Ā andĀ theĀ uptakeĀ ofĀ exogenous Ca<sup>++</sup>.Ā Ca<sup>++</sup>Ā bindingĀ isĀ stimulatedĀ byĀ 0.05Ā toĀ 0.15Ā MĀ Na<sup>+</sup>Ā orĀ K<sup>+</sup> andĀ 0.05Ā toĀ 0.25Ā MĀ Li<sup>+</sup>,Ā whereasĀ NH4<sup>+</sup>,Ā Rb<sup>+</sup>,Ā and Cs<sup>+</sup>Ā haveĀ little effectĀ orĀ areĀ inhibitoryĀ atĀ theseĀ concentrations;Ā atĀ higherĀ concentrations,Ā allĀ ofĀ theĀ alkaliĀ metalĀ cationsĀ becomeĀ inhibitory. | |||
|keywords=Ca<sup>++</sup> uptake, Respiration, Phosphorylation | |||
}} | }} | ||
{{Labeling | {{Labeling | ||
|area=Respiration | |||
|organism=Rat | |||
|tissues=Kidney | |||
|preparations=Isolated mitochondria | |||
|topics=ADP, Calcium, Coupling efficiency;uncoupling, Inhibitor, Ion;substrate transport | |||
|additional=Made history | |additional=Made history | ||
}} | }} |
Latest revision as of 11:23, 28 May 2015
Vasington FD, Murphy JV (1962) Ca++ uptake by rat kidney mitochondria and its dependence on respiration and phosphorylation. J Biol Chem 237:2670-7. |
Ā» PMID: 13925019 Open Access; PDF
Vasington FD, Murphy JV (1962) J Biol Chem
Abstract: Rat kidney mitochondria bind large quantities of Ca++. Maximal Ca++ binding requires the presence o f a respiratory substrate such as isocitrate or succinate, as well as adenosine triphosphate (ATP), inorganic orthophosphate (Pi), and Mg++. No Ca++ is bound in the absence of ATP, whereas if Pi or Mg++ is omitted, the amount of Ca++ bound is decreased 40 to 70%. Adenosine diphosphate (ADP) can substitute partially for ATP, presumably through formation of ATP by adenylate kinase, but other nucleoside di- and triphosphates tested are essentially inactive.
Respiratory inhibitors such as Amytal, antimycin A, cyanide, and azide inhibit Ca++ binding, as do uncoupling agents such as dinitrophenol, dicoumarol, and gramicidin. Significantly, Ca++ is bound by mitochondria even in the presence of uncoupling quantities of Ca++. Dinitrophenol and other uncoupling agents therefore block Ca++ binding under conditions in which phosphorylation is already uncoupled by Ca++.
Endogenous Ca++ is released from mitochondria incubated in the absence of ATP or ADP or in the presence of antimycin A, dinitrophenol, or HgC12, suggesting that similar factors influence the retention of endogenous Ca++ and the uptake of exogenous Ca++. Ca++ binding is stimulated by 0.05 to 0.15 M Na+ or K+ and 0.05 to 0.25 M Li+, whereas NH4+, Rb+, and Cs+ have little effect or are inhibitory at these concentrations; at higher concentrations, all of the alkali metal cations become inhibitory. ā¢ Keywords: Ca++ uptake, Respiration, Phosphorylation
Labels: MiParea: Respiration
Organism: Rat
Tissue;cell: Kidney
Preparation: Isolated mitochondria
Regulation: ADP, Calcium, Coupling efficiency;uncoupling, Inhibitor, Ion;substrate transport
Made history