What question did this study set out to answer?

To measure the steady-state concentrations of coenzyme A derivatives and tricarboxylate cycle intermediates during substrate oxidation across varying respiratory states in isolated rabbit heart mitochondria.

November 1, 1975Journal of Biological ChemistryOpen Access

The steady state concentrations of coenzyme A-SH and coenzyme A thioester, citrate, and isocitrate during tricarboxylate cycle oxidations in rabbit heart mitochondria.

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Authors

RHRG Hansford RJR N JohnsonEmory University

Discussion

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Implication

In vitro study demonstrates dynamic shifts in coenzyme A thioester pools during respiratory transitions in rabbit heart mitochondria, suggesting flux limitation by citrate synthase.

Key Points

To measure the steady-state concentrations of coenzyme A derivatives and tricarboxylate cycle intermediates during substrate oxidation across varying respiratory states in isolated rabbit heart mitochondria.
Quantified intramitochondrial levels of coenzyme A-SH, acetyl-CoA, succinyl-CoA, and long-chain acyl-CoA during the oxidation of palmitoylcarnitine, octanoate, or pyruvate with L-malate.
Assessed intermediate respiratory states (state 3 1/2) using a glucose and hexokinase ADP-regenerating system alongside standard state 4 to state 3 transitions.
Identified that the Michaelis constant (Km) of beta-oxidation for intramitochondrial long-chain acyl-CoA is approximately 1 nmol/mg of mitochondrial protein.
Transition from state 4 to ADP-stimulated state 3 respiration decreased acetyl-CoA and increased coenzyme A-SH and succinyl-CoA across all substrate conditions, reversing upon ADP depletion.
Intermediate respiratory states exhibited marked elevations in succinyl-CoA relative to states 3 or 4, indicating suboptimal flux governed by citrate synthase.

Cite This Study

Hansford et al. (1975) studied this question.

synapsesocial.com/papers/6a6fee4d2163a0a01bc42963 https://doi.org/10.1016/s0021-9258(19)40767-9

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Implication

In vitro study demonstrates dynamic shifts in coenzyme A thioester pools during respiratory transitions in rabbit heart mitochondria, suggesting flux limitation by citrate synthase.

The steady state concentrations of coenzyme A-SH and coenzyme A thioester, citrate, and isocitrate during tricarboxylate cycle oxidations in rabbit heart mitochondria.

Discussion

Member takes

Implication

Key Points

Cite This Study

The steady state concentrations of coenzyme A-SH and coenzyme A thioester, citrate, and isocitrate during tricarboxylate cycle oxidations in rabbit heart mitochondria.

Discussion

Member takes

Implication

Key Points

Cite This Study

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