IUBMB Enzyme Nomenclature


Accepted name: cyanuric acid amidohydrolase

Reaction: cyanuric acid + H2O = 1-carboxybiuret

For diagram of reaction click here.

Glossary: cyanuric acid = 1,3,5-triazine-2,4,6(1H,3H,5H)-trione = 2,4,6-trihydroxy-s-triazine
1-carboxybiuret = N-[(carbamoylamino)carbonyl]carbamate

Other name(s): atzD (gene name); trzD (gene name)

Systematic name: cyanuric acid amidohydrolase

Comments: The enzyme catalyses the ring cleavage of cyanuric acid, an intermediate in the degradation of s-triazide herbicides such as atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-1,3,5-triazine]. The enzyme is highly specific for cyanuric acid. The product was initially thought to be bioret, but was later shown to be 1-carboxybioret.

Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 132965-78-7


1. Eaton, R.W. and Karns, J.S. Cloning and comparison of the DNA encoding ammelide aminohydrolase and cyanuric acid amidohydrolase from three s-triazine-degrading bacterial strains. J. Bacteriol. 173 (1991) 1363-1366. [PMID: 1991731]

2. Eaton, R.W. and Karns, J.S. Cloning and analysis of s-triazine catabolic genes from Pseudomonas sp. strain NRRLB-12227. J. Bacteriol. 173 (1991) 1215-1222. [PMID: 1846859]

3. Karns, J.S. Gene sequence and properties of an s-triazine ring-cleavage enzyme from Pseudomonas sp. strain NRRLB-12227. Appl. Environ. Microbiol. 65 (1999) 3512-3517. [PMID: 10427042]

4. Fruchey, I., Shapir, N., Sadowsky, M.J. and Wackett, L.P. On the origins of cyanuric acid hydrolase: purification, substrates, and prevalence of AtzD from Pseudomonas sp. strain ADP. Appl. Environ. Microbiol. 69 (2003) 3653-3657. [PMID: 12788776]

5. Esquirol, L., Peat, T.S., Wilding, M., Liu, J.W., French, N.G., Hartley, C.J., Onagi, H., Nebl, T., Easton, C.J., Newman, J. and Scott, C. An unexpected vestigial protein complex reveals the evolutionary origins of an s-triazine catabolic enzyme. J. Biol. Chem 293 (2018) 7880-7891. [PMID: 29523689]

[EC created 2000, modified 2008, modified 2019]

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