EC - Ornithine cyclodeaminase

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IntEnz Enzyme Nomenclature


Accepted name:
ornithine cyclodeaminase
Other names:
ornithine cyclase
ornithine cyclase (deaminating)
L-ornithine ammonia-lyase (cyclizing)
Systematic name:
L-ornithine ammonia-lyase (cyclizing; L-proline-forming)




Requires NAD+. The enzyme is a member of the μ-crystallin protein family [4]. The reaction is stimulated by the presence of ADP or ATP and is inhibited by O2 [2].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0008473
CAS Registry Number: 9054-76-6


  1. Costilow, R.N. and Laycock, L.
    Ornithine cyclase (deaminating). Purification of a protein that converts ornithine to proline and definition of the optimal assay conditions.
    J. Biol. Chem. 246: 6655-6660 (1971). [PMID: 4399881]
  2. Muth, W.L. and Costilow, R.N.
    Ornithine cyclase (deaminating). II. Properties of the homogeneous enzyme.
    J. Biol. Chem. 249: 7457-7462 (1974). [PMID: 4373469]
  3. Espineda, C.E., Linford, A.S., Devine, D. and Brusslan, J.A.
    The AtCAO gene, encoding chlorophyll a oxygenase, is required for chlorophyll b synthesis in Arabidopsis thaliana.
    Proc. Natl. Acad. Sci. USA 96: 10507-10511 (1999). [PMID: 10468639]
  4. Goodman, J.L., Wang, S., Alam, S., Ruzicka, F.J., Frey, P.A. and Wedekind, J.E.
    Ornithine cyclodeaminase: structure, mechanism of action, and implications for the μ-crystallin family.
    Biochemistry 43: 13883-13891 (2004). [PMID: 15518536]
  5. Alam, S., Wang, S. C., Ruzicka, F.J., Frey, P.A. and Wedekind, J.E.
    Crystallization and X-ray diffraction analysis of ornithine cyclodeaminase from Pseudomonas putida.
    Acta Crystallogr. D Biol. Crystallogr. 60: 941-944 (2004). [PMID: 15103146]

[EC created 1976]