Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 1996 Jan 15;313(Pt 2):581–588. doi: 10.1042/bj3130581

Reduction pathway of cis-5 unsaturated fatty acids in intact rat-liver and rat-heart mitochondria: assessment with stable-isotype-labelled substrates.

K Y Tserng 1, S J Jin 1, L S Chen 1
PMCID: PMC1216947  PMID: 8573096

Abstract

Besides the conventional isomerase-mediated pathway, unsaturated fatty acids with old-numbered double bonds are also metabolized by reduction pathways with NADPH as cofactor. The relative contributions of these pathways were measured in intact rat-liver and rat-heart mitochondria with a novel stable isotope tracer technique. A mixture of equal amounts of unlabelled cis-5-enoyl-CoA and 13C4-labelled acyl-CoA of equal chain lengths was incubated with mitochondria. The isotope distribution of 3-hydroxy fatty acids produced from the first cycle of beta-oxidation was analysed with selected ion monitoring by gas chromatograph-mass spectrometer. 3-Hydroxy fatty acids produced from the reduction pathway of unsaturated fatty acids were unlabelled (m + 0) whereas those produced from saturated fatty acids were labelled (m + 4). The m + 0 content serves to indicate the extent of reduction pathway. Rotenone treatment was used to switch the pathway completely to reduction. The extent of m + 0 enrichment in untreated mitochondria normalized to the m + 0 enrichment of rotenone-treated mitochondria was the percentage of reduction pathway. With this technique, cis-4-decenoate was found to be metabolized completely by the reduction pathway in both liver and heart mitochondria. cis-5-Dodecenoate was metabolized essentially by the reduction pathway in liver mitochondria, but only to 75% in heart mitochondria. When the chain length was extended to cis-5-tetradecenoate, the reduction pathway in liver mitochondria decreased to 86% and that in heart mitochondria to 65%. The effects of carnitine, clofibrate and other conditions on the reduction pathway were also studied. Enrichments of the label on saturated fatty acids and 3-hydroxy fatty acids indicated that the major pathway of reduction was not by the direct reduction of the cis-5 double bond. Instead, it is most probably by a pathway that does not involve forming a reduced saturated fatty acid first.

Full Text

The Full Text of this article is available as a PDF (388.8 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Chen L. S., Jin S. J., Dejak I., Tserng K. Y. Isomerization of trans-2,delta 5-dienoyl-CoA's to delta 3,delta 5-dienoyl-CoA's in the beta-oxidation of delta 5-unsaturated fatty acids. Biochemistry. 1995 Jan 17;34(2):442–450. doi: 10.1021/bi00002a008. [DOI] [PubMed] [Google Scholar]
  2. Chen L. S., Jin S. J., Tserng K. Y. Purification and mechanism of delta 3,delta 5-t-2,t-4-dienoyl-CoA isomerase from rat liver. Biochemistry. 1994 Aug 30;33(34):10527–10534. doi: 10.1021/bi00200a039. [DOI] [PubMed] [Google Scholar]
  3. Dommes V., Baumgart C., Kunau W. H. Degradation of unsaturated fatty acids in peroxisomes. Existence of a 2,4-dienoyl-CoA reductase pathway. J Biol Chem. 1981 Aug 25;256(16):8259–8262. [PubMed] [Google Scholar]
  4. ELLMAN G. L. Tissue sulfhydryl groups. Arch Biochem Biophys. 1959 May;82(1):70–77. doi: 10.1016/0003-9861(59)90090-6. [DOI] [PubMed] [Google Scholar]
  5. Greter J., Lindstedt S., Seeman H., Steen G. 3-hydroxydecanedioic acid and related homologues: urinary metabolites in ketoacidosis. Clin Chem. 1980 Feb;26(2):261–265. [PubMed] [Google Scholar]
  6. Hoek J. B., Rydström J. Physiological roles of nicotinamide nucleotide transhydrogenase. Biochem J. 1988 Aug 15;254(1):1–10. doi: 10.1042/bj2540001. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Jin S. J., Hoppel C. L., Tserng K. Y. Incomplete fatty acid oxidation. The production and epimerization of 3-hydroxy fatty acids. J Biol Chem. 1992 Jan 5;267(1):119–125. [PubMed] [Google Scholar]
  8. Jin S. J., Tserng K. Y. Metabolic origins of urinary unsaturated dicarboxylic acids. Biochemistry. 1990 Sep 18;29(37):8540–8547. doi: 10.1021/bi00489a006. [DOI] [PubMed] [Google Scholar]
  9. Kimura C., Kondo A., Koeda N., Yamanaka H., Mizugaki M. Studies on the metabolism of unsaturated fatty acids. XV. Purification and properties of 2,4-dienoyl-CoA reductase from rat liver peroxisomes. J Biochem. 1984 Nov;96(5):1463–1469. doi: 10.1093/oxfordjournals.jbchem.a134975. [DOI] [PubMed] [Google Scholar]
  10. Luo M. J., Smeland T. E., Shoukry K., Schulz H. Delta 3,5, delta 2,4-dienoyl-CoA isomerase from rat liver mitochondria. Purification and characterization of a new enzyme involved in the beta-oxidation of unsaturated fatty acids. J Biol Chem. 1994 Jan 28;269(4):2384–2388. [PubMed] [Google Scholar]
  11. Lê-Quôc D., Lê-Quôc K. Relationships between the NAD(P) redox state, fatty acid oxidation, and inner membrane permeability in rat liver mitochondria. Arch Biochem Biophys. 1989 Sep;273(2):466–478. doi: 10.1016/0003-9861(89)90506-7. [DOI] [PubMed] [Google Scholar]
  12. Mizugaki M., Nishimaki T., Yamamoto H., Sagi M., Yamanaka H. Studies on the metabolism of unsaturated fatty acids. XI. Alterations in the activities of enoyl-CoA hydratase, 3-hydroxyacyl-CoA epimerase and 2,4-dienyl-CoA reductase in rat liver mitochondria and peroxisomes by clofibrate. J Biochem. 1982 Dec;92(6):2051–2054. doi: 10.1093/oxfordjournals.jbchem.a134140. [DOI] [PubMed] [Google Scholar]
  13. Osmundsen H., Cervenka J., Bremer J. A role for 2,4-enoyl-CoA reductase in mitochondrial beta-oxidation of polyunsaturated fatty acids. Effects of treatment with clofibrate on oxidation of polyunsaturated acylcarnitines by isolated rat liver mitochondria. Biochem J. 1982 Dec 15;208(3):749–757. doi: 10.1042/bj2080749. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Schulz H. Long chain enoyl coenzyme A hydratase from pig heart. J Biol Chem. 1974 May 10;249(9):2704–2709. [PubMed] [Google Scholar]
  15. Schulz H. Regulation of fatty acid oxidation in heart. J Nutr. 1994 Feb;124(2):165–171. doi: 10.1093/jn/124.2.165. [DOI] [PubMed] [Google Scholar]
  16. Smeland T. E., Nada M., Cuebas D., Schulz H. NADPH-dependent beta-oxidation of unsaturated fatty acids with double bonds extending from odd-numbered carbon atoms. Proc Natl Acad Sci U S A. 1992 Aug 1;89(15):6673–6677. doi: 10.1073/pnas.89.15.6673. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Stein R. A. Fractionation of methyl d-tetracosanoates by GCMS. Chem Phys Lipids. 1976 Sep;17(1):22–27. doi: 10.1016/0009-3084(76)90033-5. [DOI] [PubMed] [Google Scholar]
  18. Stoffel W., Caesar H. Der Stoffwechsel der ungesättigten Fettsäuren. V. Zur beta-Oxydation der Mono- und Polyenfettsäuren. Der Mechanismus der enzymatischen Reaktionen an delta-2-cis-Enoyl-CoA-Verbindungen. Hoppe Seylers Z Physiol Chem. 1965;341(1):76–83. [PubMed] [Google Scholar]
  19. Tomec R. J., Hoppel C. L. Carnitine palmitoyltransferase in bovine fetal heart mitochondria. Arch Biochem Biophys. 1975 Oct;170(2):716–723. doi: 10.1016/0003-9861(75)90169-1. [DOI] [PubMed] [Google Scholar]
  20. Tserng K. Y., Chen L. S., Jin S. J. Comparison of metabolic fluxes of cis-5-enoyl-CoA and saturated acyl-CoA through the beta-oxidation pathway. Biochem J. 1995 Apr 1;307(Pt 1):23–28. doi: 10.1042/bj3070023. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Tserng K. Y., Jin S. J. Metabolic origin of urinary 3-hydroxy dicarboxylic acids. Biochemistry. 1991 Mar 5;30(9):2508–2514. doi: 10.1021/bi00223a030. [DOI] [PubMed] [Google Scholar]
  22. Tserng K. Y., Jin S. J. NADPH-dependent reductive metabolism of cis-5 unsaturated fatty acids. A revised pathway for the beta-oxidation of oleic acid. J Biol Chem. 1991 Jun 25;266(18):11614–11620. [PubMed] [Google Scholar]
  23. Tserng K. Y., Jin S. J. Oxidation of cis-5-unsaturated fatty acids in intact rat liver mitochondria: the operation of reduction pathways. Biochem J. 1995 May 15;308(Pt 1):39–44. doi: 10.1042/bj3080039. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Tserng K. Y., Kalhan S. C. Calculation of substrate turnover rate in stable isotope tracer studies. Am J Physiol. 1983 Sep;245(3):E308–E311. doi: 10.1152/ajpendo.1983.245.3.E308. [DOI] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES