EC - Chloromuconate cycloisomerase

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IntEnz Enzyme Nomenclature


Accepted name:
chloromuconate cycloisomerase
Other names:
muconate cycloisomerase II
2-chloro-2,5-dihydro-5-oxofuran-2-acetate lyase (decyclizing)
2-chloro-2,5-dihydro-5-oxofuran-2-acetate lyase (ring-opening)
Systematic name:
(2R)-2-chloro-2,5-dihydro-5-oxofuran-2-acetate lyase (ring-opening)




Requires Mn2+. The product of cycloisomerization of 3-chloro-cis,cis-muconate spontaneously eliminates chloride to produce cis-4-carboxymethylenebut-2-en-4-olide. Also acts (in the reverse direction) on 2-chloro-cis,cis-muconate. Not identical with EC (muconate cycloisomerase) or EC (dichloromuconate cycloisomerase).

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UM-BBD , UniPathway
Protein domains and families: PROSITE:PDOC00706
Structural data: CSA , EC2PDB
Gene Ontology: GO:0018850
CAS Registry Number: 95990-33-3


  1. Schmidt, E. and Knackmuss, H.-J.
    Chemical structure and biodegradability of halogenated aromatic compounds. Conversion of chlorinated muconic acids into maleoylacetic acid.
    Biochem. J. 192: 339-347 (1980). [PMID: 7305906]
  2. Kaulmann, U., Kaschabek, S. R., Schlomann, M.
    Mechanism of chloride elimination from 3-chloro- and 2,4-dichloro-cis,cis-muconate: new insight obtained from analysis of muconate cycloisomerase variant CatB-K169A.
    J. Bacteriol. 183: 4551-4561 (2001). [PMID: 11443090]
  3. Kajander, T., Lehtio, L., Schlomann, M., Goldman, A.
    The structure of Pseudomonas P51 Cl-muconate lactonizing enzyme: co-evolution of structure and dynamics with the dehalogenation function.
    Protein Sci. 12: 1855-1864 (2003). [PMID: 12930985]

[EC created 1983]