13C isotopomer model for estimation of anaplerotic substrate oxidation via acetyl-CoA

F. Mark H Jeffrey, Charles J. Storey, A. Dean Sherry, Craig R. Malloy

Research output: Contribution to journalArticle

57 Scopus citations

Abstract

A previous model using 13C nuclear magnetic resonance isotopomer analysis provided for direct measurement of the oxidation of 13C-enriched substrates in the tricarboxylic acid cycle and/or their entry via anaplerotic pathways. This model did not allow for recycling of labeled metabolites from tricarboxylic acid cycle intermediates into the acetyl-CoA pool. An extension of this model is now presented that incorporates carbon flow from oxaloacetate or malate to acetyl-CoA. This model was examined using propionate metabolism in the heart, in which previous observations indicated that all of the propionate consumed was oxidized to CO2 and water. Application of the new isotopomer model shows that 2 mM [3-13C]propionate entered the tricarboxylic acid cycle as succinyl-CoA (an anaplerotic pathway) at a rate equal to 52% of tricarboxylic acid cycle turnover and that all of this carbon entered the acetyl-CoA pool and was oxidized. This was verified using standard biochemical analysis; from the rate (μmol · min-1 · g dry wt-1) of propionate uptake (4.0 ± 0.7), the estimated oxygen consumption (24.8 ± 5) matched that experimentally determined (24.4 ± 3).

Original languageEnglish (US)
Pages (from-to)E788-E799
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume271
Issue number4 34-4
StatePublished - Oct 1 1996

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Keywords

  • anaplerosis
  • carbon-13 nuclear magnetic resonance
  • isotopomer analysis
  • tricarboxylic acid cycle

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Physiology (medical)

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