IUBMB Enzyme Nomenclature


Accepted name: chloromuconate cycloisomerase

Reaction: (2R)-2-chloro-2,5-dihydro-5-oxofuran-2-acetate = 3-chloro-cis,cis-muconate

For diagram click here.

Glossary: (2R)-2-chloro-2,5-dihydro-5-oxofuran-2-acetate = (+)-4-chloromuconolactone
3-chloro-cis,cis-muconate = (2E,4Z)-3-chlorohexa-2,4-dienedioate

Other name(s): 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)

Comments: 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: BRENDA, EAWAG-BBD, EXPASY, KEGG, Metacyc, PDB, 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 (1980) 339-347. [PMID: 7305906]

2. Kaulmann, U., Kaschabek, S.R. and 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 (2001) 4551-4561. [PMID: 11443090]

3. Kajander, T., Lehtio, L., Schlomann, M. and Goldman, A. The structure of Pseudomonas P51 Cl-muconate lactonizing enzyme: co-evolution of structure and dynamics with the dehalogenation function. Protein Sci. 12 (2003) 1855-1864. [PMID: 12930985]

[EC created 1983]

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