IUBMB Enzyme Nomenclature


Accepted name: ornithine cyclodeaminase

Reaction: L-ornithine = L-proline + NH3

For diagram click here.

Other name(s): ornithine cyclase; ornithine cyclase (deaminating); L-ornithine ammonia-lyase (cyclizing)

Systematic name: L-ornithine ammonia-lyase (cyclizing; L-proline-forming)

Comments: 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: BRENDA, EXPASY, KEGG, Metacyc, 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 (1971) 6655-6660. [PMID: 4399881]

2. Muth, W.L. and Costilow, R.N. Ornithine cyclase (deaminating). II. Properties of the homogeneous enzyme. J. Biol. Chem. 249 (1974) 7457-7462. [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 (1999) 10507-10511. [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 (2004) 13883-13891. [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 (2004) 941-944. [PMID: 15103146]

[EC created 1976]

Return to EC 4.3.1 home page
Return to EC 4.3 home page
Return to EC 4 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page