Further studies on the effect of phosphoenolpyruvate on respiration-dependent calcium transport by rat heart mitochondria

Phosphoenolpyruvate was found to depress extra oxygen consumption associated with Ca 2+ -induced respiratory jump by rat heart mitochondria. Addition of phosphoenolpyruvate to mitochondria which have accumulated Ca 2+ in the presence of glutamate and inorganic phosphate causes the release of Ca 2+ f...

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Bibliographic Details
Main Author: Prakorn Chudapongse
Other Authors: Mahidol University
Format: Article
Published: 2018
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Online Access:https://repository.li.mahidol.ac.th/handle/123456789/10841
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Institution: Mahidol University
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Summary:Phosphoenolpyruvate was found to depress extra oxygen consumption associated with Ca 2+ -induced respiratory jump by rat heart mitochondria. Addition of phosphoenolpyruvate to mitochondria which have accumulated Ca 2+ in the presence of glutamate and inorganic phosphate causes the release of Ca 2+ from mitochondria. The phosphoenolpyruvate-stimulated Ca 2+ efflux can be observed with mitochondria loaded with low initial Ca 2+ concentration (0.12 mM) in the incubation medium. Measurements of mitochondrial H + translocation produced by addition of Ca 2+ to respiring mitochondria show that phosphoenolpyruvate depresses H + ejection and enhances H + uptake by mitochondria. The Ca 2+ -releasing effect of phosphoenolpyruvate was found to be significantly stronger than that produced by rotenone when added to mitochondria loaded with Ca 2+ in the presence of glutamate and inorganic phosphate. Dithiothreitol cannot overcome the effect of phosphoenolpyruvate on mitochondrial Ca 2+ transport. © 1976.