IUBMB Enzyme Nomenclature


Accepted name: 2-oxo-3-hexenedioate decarboxylase

Reaction: (3E)-2-oxohex-3-enedioate = 2-oxopent-4-enoate + CO2

For diagram of reaction click here.

Other name(s): 4-oxalocrotonate carboxy-lyase (misleading); 4-oxalocrotonate decarboxylase (misleading); cnbF (gene name); praD (gene name); amnE (gene name); nbaG (gene name); xylI (gene name)

Systematic name: (3E)-2-oxohex-3-enedioate carboxy-lyase (2-oxopent-4-enoate-forming)

Comments: Involved in the meta-cleavage pathway for the degradation of phenols, modified phenols and catechols. The enzyme has been reported to accept multiple tautomeric forms [1-4]. However, careful analysis of the stability of the different tautomers, as well as characterization of the enzyme that produces its substrate, EC, 2-hydroxymuconate tautomerase, showed that the actual substrate for the enzyme is (3E)-2-oxohex-3-enedioate [4].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, UM-BBD, CAS registry number: 37325-55-6


1. Shingler, V., Marklund, U., Powlowski, J. Nucleotide sequence and functional analysis of the complete phenol/3,4-dimethylphenol catabolic pathway of Pseudomonas sp. strain CF600. J. Bacteriol. 174 (1992) 711-724. [PMID: 1732207]

2. Takenaka, S., Murakami, S., Shinke, R. and Aoki, K. Metabolism of 2-aminophenol by Pseudomonas sp. AP-3: modified meta-cleavage pathway. Arch. Microbiol. 170 (1998) 132-137. [PMID: 9683650]

3. Stanley, T.M., Johnson, W.H., Jr., Burks, E.A., Whitman, C.P., Hwang, C.C. and Cook, P.F. Expression and stereochemical and isotope effect studies of active 4-oxalocrotonate decarboxylase. Biochemistry 39 (2000) 718-726. [PMID: 10651637]

4. Wang, S.C., Johnson, W.H., Jr., Czerwinski, R.M., Stamps, S.L. and Whitman, C.P. Kinetic and stereochemical analysis of YwhB, a 4-oxalocrotonate tautomerase homologue in Bacillus subtilis: mechanistic implications for the YwhB- and 4-oxalocrotonate tautomerase-catalyzed reactions. Biochemistry 46 (2007) 11919-11929. [PMID: 17902707]

5. Kasai, D., Fujinami, T., Abe, T., Mase, K., Katayama, Y., Fukuda, M. and Masai, E. Uncovering the protocatechuate 2,3-cleavage pathway genes. J. Bacteriol. 191 (2009) 6758-6768. [PMID: 19717587]

[EC created 1999, modified 2011, modified 2012]

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