Evidence for a short-chain carnitine-acylcarnitine translocase in mitochondria specifically related to the metabolism of branched-chain amino acids

Diane S. Roe, Charles R. Roe, Michèle Brivet, Lawrence Sweetman

Research output: Contribution to journalArticlepeer-review

Abstract

Carnitine-acylcarnitine translocase (CATR) deficiency is a severe defect in fatty acid oxidation which presents early in life most frequently with hypoglycemia, hyperammonemia, and severe cardiac abnormalities. CATR exchanges acylcarnitines of various chain lengths for free carnitine across the mitochondrial membrane. In vitro studies in intact fibroblasts from patients with documented deficiency of CATR were probed with stable-isotope- labeled precursors and the resulting acylcarnitines were analyzed by tandem mass spectrometry. After a 72-h incubation with L-[2H3]carnitine the translocase-deficient cells produced acylcarnitines in which the deuterium was incorporated into short-chain acylcarnitines, C2-C5. Experiments with simultaneous incubation of L-[2H3]carnitine and L-[13C6]isoleucine produced [13C5]2-methylbutyryl[2H3]carnitine and [13C3]propionyl- [2H3]carnitine indicating exchange of labeled acylcarnitine from inside the mitochondrial matrix with labeled free carnitine. These studies support the possible existence of a 'branched-chain' carnitine-acylcarnitine translocator in mitochondria. (C) 2000 Academic Press.

Original languageEnglish (US)
Pages (from-to)69-75
Number of pages7
JournalMolecular genetics and metabolism
Volume69
Issue number1
DOIs
StatePublished - Jan 2000
Externally publishedYes

Keywords

  • Branched-chain amino acids
  • Carnitine-acylcarnitine translocase
  • L- carnitine
  • Tandem mass spectrometry

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Endocrinology

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