IUBMB Enzyme Nomenclature


Accepted name: L-ornithine N5-monooxygenase (NADPH)

Reaction: L-ornithine + NADPH + H+ + O2 = N5-hydroxy-L-ornithine + NADP+ + H2O

Other name(s): CchB; ornithine hydroxylase; EtcB; PvdA; Af-OMO; dffA (gene name)

Systematic name: L-ornithine,NADPH:oxygen oxidoreductase (N5-hydroxylating)

Comments: A flavoprotein (FAD). The enzyme is involved in biosynthesis of N5-hydroxy-L-ornithine, N5-formyl-N5-hydroxy-L-ornithine or N5-acetyl-N5-hydroxy-L-ornithine. These nonproteinogenic amino acids are building blocks of siderophores produced by some bacteria (e.g. Streptomyces coelicolor, Saccharopolyspora erythraea and Pseudomonas aeruginosa). The enzyme is specific for NADPH. cf. EC, L-ornithine N5-monooxygenase [NAD(P)H].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Ge, L. and Seah, S.Y. Heterologous expression, purification, and characterization of an L-ornithine N5-hydroxylase involved in pyoverdine siderophore biosynthesis in Pseudomonas aeruginosa. J. Bacteriol. 188 (2006) 7205-7210. [PMID: 17015659]

2. Meneely, K.M. and Lamb, A.L. Biochemical characterization of a flavin adenine dinucleotide-dependent monooxygenase, ornithine hydroxylase from Pseudomonas aeruginosa, suggests a novel reaction mechanism. Biochemistry 46 (2007) 11930-11937. [PMID: 17900176]

3. Pohlmann, V. and Marahiel, M.A. δ-amino group hydroxylation of L-ornithine during coelichelin biosynthesis. Org. Biomol. Chem. 6 (2008) 1843-1848. [PMID: 18452021]

4. Robbel, L., Helmetag, V., Knappe, T.A. and Marahiel, M.A. Consecutive enzymatic modification of ornithine generates the hydroxamate moieties of the siderophore erythrochelin. Biochemistry 50 (2011) 6073-6080. [PMID: 21650455]

[EC created 2014]

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