Ornithine cyclodeaminase explained

The enzyme ornithine cyclodeaminase (EC 4.3.1.12) catalyzes the chemical reaction

L-ornithine

L-proline + NH₄⁺

This enzyme belongs to the family of lyases, specifically ammonia lyases, which cleave carbon-nitrogen bonds. The systematic name of this enzyme class is Lornithine ammonia-lyase (cyclizing; L-proline-forming). Other names in common use include ornithine cyclase, ornithine cyclase (deaminating), and L-ornithine ammonia-lyase (cyclizing). This enzyme participates in arginine and proline biosynthesis. It employs one cofactor, NAD⁺.

Structural studies

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and .

References

• Costilow RN, Laycock L . 1971 . Ornithine cyclase (deaminating). Purification of a protein that converts ornithine to proline and definition of the optimal assay conditions . . 246 . 6655 - 60 . 4399881 . 21 . 10.1016/S0021-9258(19)34165-1 . free .
• Muth WL, Costilow RN . 1974 . Ornithine cyclase (deaminating). II. Properties of the homogeneous enzyme . . 249 . 7457 - 62 . 4373469 . 23 . 10.1016/S0021-9258(19)81260-7 . free .
• Espineda CE, Linford AS, Devine D, Brusslan JA . 1999 . The AtCAO gene, encoding chlorophyll a oxygenase, is required for chlorophyll b synthesis in Arabidopsis thaliana . . 96 . 10507 - 11 . 10468639 . 10.1073/pnas.96.18.10507 . 18 . 17919 . 1999PNAS...9610507E . free .
• Goodman JL, Wang S, Alam S, Ruzicka FJ, Frey PA, Wedekind JE . 2004 . Ornithine cyclodeaminase: structure, mechanism of action, and implications for the mu-crystallin family . . 43 . 13883 - 91 . 15518536 . 10.1021/bi048207i . 44 .
• Alam S, Wang SC, Ruzicka FJ, Frey PA, Wedekind JE . 2004 . Crystallization and X-ray diffraction analysis of ornithine cyclodeaminase from Pseudomonas putida . . 60 . 941 - 4 . 15103146 . 10.1107/S0907444904005256 . Pt 5 .