EC - (R)-3-(aryl)lactoyl-CoA dehydratase

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IntEnz Enzyme Nomenclature


Accepted name:
(R)-3-(aryl)lactoyl-CoA dehydratase
Other names:
(R)-phenyllactoyl-CoA dehydratase
aryllactyl-CoA dehydratase
Systematic name:
(R)-3-(aryl)lactoyl-CoA hydro-lyase



The enzyme, found in some amino acid-fermenting anaerobic bacteria, participates in the fermentation pathways of L-phenylalanine, L-tyrosine, and L-tryptophan. It is a heterodimeric protein consisting of the FldB and FldC polypeptides, both of which contain an [4Fe-4S] cluster, and forms a complex with EC, 3-(aryl)acryloyl-CoA:(R)-3-(aryl)lactate CoA-transferase (FldA). In order to catalyse the reaction, the enzyme requires one high-energy electron that transiently reduces the electrophilic thiol ester carbonyl of the substrate to a nucleophilic ketyl radical anion, facilitating the elimination of the hydroxyl group. This electron, which is provided by by EC, (R)-2-hydroxyacyl-CoA dehydratase activating ATPase, needs to be supplied only once, before the first reaction takes place, as it is regenerated at the end of each reaction cycle. The enzyme acts on (R)-3-(aryl)lactoyl-CoAs produced by FldA, and regenerates the CoA donors used by that enzyme.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Dickert, S., Pierik, A. J., Linder, D., Buckel, W.
    The involvement of coenzyme A esters in the dehydration of (R)-phenyllactate to (E)-cinnamate by Clostridium sporogenes.
    Eur. J. Biochem. 267 : 3874-3884 (2000). [PMID: 10849007]
  2. Dickert, S., Pierik, A. J., Buckel, W.
    Molecular characterization of phenyllactate dehydratase and its initiator from Clostridium sporogenes.
    Mol. Microbiol. 44 : 49-60 (2002). [PMID: 11967068]
  3. Kim, J., Hetzel, M., Boiangiu, C. D., Buckel, W.
    Dehydration of (R)-2-hydroxyacyl-CoA to enoyl-CoA in the fermentation of alpha-amino acids by anaerobic bacteria.
    FEMS Microbiol. Rev. 28 : 455-468 (2004). [PMID: 15374661]
  4. Kim, J., Darley, D. J., Buckel, W., Pierik, A. J.
    An allylic ketyl radical intermediate in clostridial amino-acid fermentation.
    Nature 452 : 239-242 (2008). [PMID: 18337824]
  5. Dodd, D., Spitzer, M. H., Van Treuren, W., Merrill, B. D., Hryckowian, A. J., Higginbottom, S. K., Le, A., Cowan, T. M., Nolan, G. P., Fischbach, M. A., Sonnenburg, J. L.
    A gut bacterial pathway metabolizes aromatic amino acids into nine circulating metabolites.
    Nature 551 : 648-652 (2017). [PMID: 29168502]

[EC created 2019]