Functional characterization of Δ32-enoyl-CoA isomerases from rat liver

Dongyan Zhang, Wenfeng Yu, Brian V. Geisbrecht, Stephen J. Gould, Howard Sprecher, Horst Schulz

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42 Scopus citations


The degradation of unsaturated fatty acids by β-oxidation involves Δ32-enoyl-CoA isomerases (enoyl-CoA isomerases) that catalyze 3-cis → 2-trans and 3-trans → 2-trans isomerizations of enoyl-CoAs and the 2,5 → 3,5 isomerization of dienoyl-CoAs. An analysis of rat liver enoyl-CoA isomerases revealed the presence of a monofunctional enoyl-CoA isomerase (ECI) in addition to mitochondrial enoyl-CoA isomerase (MECI) in mitochondria, whereas peroxisomes contain ECI and multifunctional enzyme 1 (MFE1). Thus ECI, which previously had been described as peroxisomal enoyl-CoA isomerase, was found to be present in both peroxisomes and mitochondria. This enzyme seems to be identical with mitochondrial long-chain enoyl-CoA isomerase (Kilponen, J.M., Palosaari, P.M., and Hiltunen, J.K. 1990. Biochem. J. 269, 223-226). All three hepatic enoyl-CoA isomerases have broad chain length specificities but are distinguishable by their preferences for one of the three isomerization reactions. MECI is most active in catalyzing the 3-cis → 2-trans isomerization; ECI has a preference for the 3-trans → 2-trans isomerization, and MFE1 is the optimal isomerase for the 2,5 → 3,5 isomerization. A functional characterization based on substrate specificities and total enoyl-CoA isomerase activities in rat liver leads to the conclusion that the 3-cis → 2-trans and 2,5 → 3,5 isomerizations in mitochondria are catalyzed overwhelmingly by MECI, whereas ECI contributes significantly to the 3-trans → 2-trans isomerization. In peroxisomes, ECI is predicted to be the dominant enzyme for the 3-cis → 2-trans and 3-trans → 2-trans isomerizations of long-chain intermediates, whereas MFE1 is the key enzyme in the 2,5 → 3,5 isomerization.

Original languageEnglish (US)
Pages (from-to)9127-9132
Number of pages6
JournalJournal of Biological Chemistry
Issue number11
StatePublished - Mar 15 2002
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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