Difference between revisions of "Vasington 1962 J Biol Chem"
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EndogenousĀ Ca++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++Ā andĀ theĀ uptakeĀ ofĀ exogenous Ca++.Ā Ca++Ā bindingĀ isĀ stimulatedĀ byĀ 0.05Ā toĀ 0.15Ā MĀ Na+Ā orĀ K+ andĀ 0.05Ā toĀ 0.25Ā MĀ Li+,Ā whereasĀ NH4+,Ā Rb+,Ā and Cs+Ā haveĀ little effectĀ orĀ areĀ inhibitoryĀ atĀ theseĀ concentrations;Ā atĀ higherĀ concentrations,Ā allĀ ofĀ theĀ alkaliĀ metalĀ cationsĀ becomeĀ inhibitory. | EndogenousĀ Ca++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++Ā andĀ theĀ uptakeĀ ofĀ exogenous Ca++.Ā Ca++Ā bindingĀ isĀ stimulatedĀ byĀ 0.05Ā toĀ 0.15Ā MĀ Na+Ā orĀ K+ andĀ 0.05Ā toĀ 0.25Ā MĀ Li+,Ā whereasĀ NH4+,Ā Rb+,Ā and Cs+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++ uptake, respiration, phosphorylation | |keywords=Ca++ uptake, respiration, phosphorylation | ||
}} | }} | ||
{{Labeling | {{Labeling | ||
|organism=Rat | |organism=Rat | ||
|tissues= | |tissues=Kidney | ||
|preparations=Isolated Mitochondria | |preparations=Isolated Mitochondria | ||
|kinetics=ADP; Pi, Inhibitor; Uncoupler | |kinetics=ADP; Pi, Inhibitor; Uncoupler | ||
Revision as of 16:56, 13 June 2012
| Vasington FD, Murphy JV (1962) Ca++ uptake by rat kidney mitochondria and its dependence on respiration and phosphorylation. J Biol Chem 237: 2670-2677. |
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:
Organism: Rat
Tissue;cell: Kidney
Preparation: Isolated Mitochondria"Isolated Mitochondria" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property.
Regulation: Ion Homeostasis"Ion Homeostasis" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property., ATP; ADP; AMP; PCr"ATP; ADP; AMP; PCr" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property.
Made history
