PROSITE documentation PDOC00150
Enoyl-CoA hydratase/isomerase signature


Enoyl-CoA hydratase (EC (ECH) [1] and D3,D2-enoyl-CoA isomerase (EC (ECI) [2] are two enzymes involved in fatty acid metabolism. ECH catalyzes the hydratation of 2-trans-enoyl-CoA into 3-hydroxyacyl-CoA and ECI shifts the 3- double bond of the intermediates of unsaturated fatty acid oxidation to the 2-trans position.

Most eukaryotic cells have two fatty-acid β-oxidation systems, one located in mitochondria and the other in peroxisomes. In mitochondria, ECH and ECI are separate yet structurally related monofunctional enzymes. Peroxisomes contain a trifunctional enzyme [3] consisting of an N-terminal domain that bears both ECH and ECI activity, and a C-terminal domain responsible for 3-hydroxyacyl-CoA dehydrogenase (HCDH) activity.

In Escherichia coli (gene fadB) and Pseudomonas fragi (gene faoA), ECH and ECI are also part of a multifunctional enzyme which contains both a HCDH and a 3-hydroxybutyryl-CoA epimerase domain [4].

A number of other proteins have been found to be evolutionary related to the ECH/ECI enzymes or domains:

  • 3-hydroxbutyryl-coa dehydratase (EC (crotonase), a bacterial enzyme involved in the butyrate/butanol-producing pathway.
  • Naphthoate synthase (EC (DHNA synthase) (gene menB) [5], a bacterial enzyme involved in the biosynthesis of menaquinone (vitamin K2). DHNA synthase converts O-succinyl-benzoyl-CoA (OSB-CoA) to 1,4-dihydroxy-2- naphthoic acid (DHNA).
  • 4-chlorobenzoate dehalogenase (EC [6], a Pseudomonas enzyme which catalyzes the conversion of 4-chlorobenzoate-CoA to 4-hydroxybenzoate-CoA.
  • A Rhodobacter capsulatus protein of unknown function (ORF257) [7].
  • Bacillus subtilis putative polyketide biosynthesis proteins pksH and pksI.
  • Escherichia coli carnitine racemase (gene caiD) [8].
  • Escherichia coli hypothetical protein ygfG.
  • Yeast hypothetical protein YDR036c.

As a signature pattern for these enzymes, we selected a conserved region rich in glycine and hydrophobic residues.

Expert(s) to contact by email:

Hofmann K.

Last update:

December 2004 / Pattern and text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

ENOYL_COA_HYDRATASE, PS00166; Enoyl-CoA hydratase/isomerase signature  (PATTERN)


1AuthorsMinami-Ishii N. Taketani S. Osumi T. Hashimoto T.
SourceEur. J. Biochem. 185:73-78(1989).

2AuthorsMueller-Newen G. Stoffel W.
SourceBiol. Chem. Hoppe-Seyler 372:613-624(1991).

3AuthorsPalosaari P.M. Hiltunen J.K.
TitlePeroxisomal bifunctional protein from rat liver is a trifunctional enzyme possessing 2-enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, and delta 3, delta 2-enoyl-CoA isomerase activities.
SourceJ. Biol. Chem. 265:2446-2449(1990).
PubMed ID2303409

4AuthorsNakahigashi K. Inokuchi H.
TitleNucleotide sequence of the fadA and fadB genes from Escherichia coli.
SourceNucleic Acids Res. 18:4937-4937(1990).
PubMed ID2204034

5AuthorsDriscoll J.R. Taber H.W.
TitleSequence organization and regulation of the Bacillus subtilis menBE operon.
SourceJ. Bacteriol. 174:5063-5071(1992).
PubMed ID1629163

6AuthorsBabbitt P.C. Kenyon G.L. Martin B.M. Charest H. Slyvestre M. Scholten J.D. Chang K.-H. Liang P.-H. Dunaway-Mariano D.
TitleAncestry of the 4-chlorobenzoate dehalogenase: analysis of amino acid sequence identities among families of acyl:adenyl ligases, enoyl-CoA hydratases/isomerases, and acyl-CoA thioesterases.
SourceBiochemistry 31:5594-5604(1992).
PubMed ID1351742

7AuthorsBeckman D.L. Kranz R.G.
TitleA bacterial homolog to the mitochondrial enoyl-CoA hydratase.
SourceGene 107:171-172(1991).
PubMed ID1743516

8AuthorsEichler K. Bourgis F. Buchet A. Kleber H.-P. Mandrand-Berthelot M.-A.
TitleMolecular characterization of the cai operon necessary for carnitine metabolism in Escherichia coli.
SourceMol. Microbiol. 13:775-786(1994).
PubMed ID7815937

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