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Vinnakota 2011 J Biol Chem

From Bioblast
Publications in the MiPMap
Vinnakota KC, Dash RK, Beard DA (2011) Stimulatory effects of calcium on respiration and NAD(P)H synthesis in intact rat heart mitochondria utilizing physiological substrates cannot explain respiratory control in vivo. J Biol Chem 286:30816-22.

Β» PMID: 21757763

Vinnakota KC, Dash RK, Beard DA (2011) J Biol Chem

Abstract: Mitochondrial TCA cycle dehydrogenase enzymes have been shown to be stimulated by Ca(2+) under various substrate and ADP incubation conditions in an attempt to determine and understand the role of Ca(2+) in maintaining energy homeostasis in working hearts. In this study, we tested the hypothesis that, at physiological temperature and 1 mM extramitochondrial free magnesium, Ca(2+) can stimulate the overall mitochondrial NAD(P)H generation flux in rat heart mitochondria utilizing pyruvate and malate as substrates at both subsaturating and saturating concentrations. In both cases, we found that, in the physiological regime of mitochondrial oxygen consumption observed in the intact animal and in the physiological range of cytosolic Ca(2+) concentration averaged per beat, Ca(2+) had no observable stimulatory effect. A modest apparent stimulatory effect (22-27%) was observable at supraphysiological maximal ADP-stimulated respiration at 2.5 mM initial phosphate. The stimulatory effects observed over the physiological Ca(2+) range are not sufficient to make a significant contribution to the control of oxidative phosphorylation in the heart in vivo.


β€’ O2k-Network Lab: US MI Ann Arbor Beard DA, US WI Milwaukee Dash RK


Labels: MiParea: Respiration 


Organism: Rat  Tissue;cell: Heart  Preparation: Isolated mitochondria 


Coupling state: LEAK, OXPHOS  Pathway:HRR: Oxygraph-2k