What question did this study set out to answer?

This research investigates the role of NADP+-linked malic enzymes in regulating the levels of tricarboxylic acid-cycle intermediates in the rat heart.

May 1, 1987Biochemical JournalOpen Access

Role of NADP+-linked malic enzymes as regulators of the pool size of tricarboxylic acid-cycle intermediates in the perfused rat heart

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Population

Isolated perfused rat hearts

Design

Preclinical

Authors

KSKaj SundqvistOulu University Hospital JHJanne HeikkiläUniversity of Oulu IHIlmo E. HassinenUniversity of Oulu

Discussion

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Implication

Does not support malic enzyme-driven cataplerosis in glucose-perfused rodent hearts; leaves open their role under high anaplerotic flux.

Key Points

This research investigates the role of NADP+-linked malic enzymes in regulating the levels of tricarboxylic acid-cycle intermediates in the rat heart.
Measured concentrations of malate, 2-oxoglutarate, isocitrate, and pyruvate using non-aqueous tissue fractionation.
Used NADP-linked isocitrate dehydrogenase as an indicator for free [NADPH]/[NADP+] ratios.
Analyzed heart perfusion with glucose and propionate to assess enzyme behavior.
NADP-linked malic enzyme ratios favored pyruvate carboxylation in both cytosolic and mitochondrial spaces during glucose perfusion.
During propionate perfusion, the enzyme ratios approached equilibrium constant, indicating differing metabolic states.
NADP-linked malic enzymes are not responsible for cataplerotic reactions during glucose metabolism but contribute under conditions of high anaplerotic flux.

Structured PICO

Population

Isolated perfused rat hearts

Intervention

Perfusion with glucose or propionate

Outcome

Cytosolic and mitochondrial concentrations of malate, 2-oxoglutarate, isocitrate and pyruvate, and mass-action ratios of NADP-linked malic enzymessurrogate

NADP-linked malic enzymes in the heart do not drive cataplerotic reactions from the TCA cycle during glucose metabolism, only allowing efflux when anaplerotic fluxes are high.

Cite This Study

Sundqvist et al. (1987) studied this question.

synapsesocial.com/papers/6a72c337ac440176ef2ad92b https://doi.org/10.1042/bj2430853

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Role of NADP+-linked malic enzymes as regulators of the pool size of tricarboxylic acid-cycle intermediates in the perfused rat heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Role of NADP+-linked malic enzymes as regulators of the pool size of tricarboxylic acid-cycle intermediates in the perfused rat heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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