Vinnakota 2016a Biophys J
|Vinnakota KC, Bazil JN, Van den Bergh F, Wiseman RW, Beard DA (2016) Feedback regulation and time hierarchy of oxidative phosphorylation in cardiac mitochondria. Biophys J 110:972-80.|
Abstract: To determine how oxidative ATP synthesis is regulated in the heart, the responses of cardiac mitochondria oxidizing pyruvate to alterations in [ATP], [ADP], and inorganic phosphate ([Pi]) were characterized over a range of steady-state levels of extramitochondrial [ATP], [ADP], and [Pi]. Evolution of the steady states of the measured variables with the flux of respiration shows that: (1) a higher phosphorylation potential is achieved by mitochondria at higher [Pi] for a given flux of respiration; (2) the time hierarchy of oxidative phosphorylation is given by phosphorylation subsystem, electron transport chain, and substrate dehydrogenation subsystems listed in increasing order of their response times; (3) the matrix ATP hydrolysis mass action ratio [ADP] × [Pi]/[ATP] provides feedback to the substrate dehydrogenation flux over the entire range of respiratory flux examined in this study; and finally, (4) contrary to previous models of regulation of oxidative phosphorylation, [Pi] does not modulate the activity of complex III.
Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved. • Keywords: Decylubiquinone
Labels: MiParea: Respiration
Organism: Rat Tissue;cell: Heart Preparation: Isolated mitochondria
Regulation: ADP, ATP, Flux control, Phosphate Coupling state: LEAK, OXPHOS Pathway: N HRR: Oxygraph-2k, TPP