IUBMB Enzyme Nomenclature


Accepted name: α-N-dichloroacetyl-p-aminophenylserinol N-oxygenase

Reaction: α-N-dichloroacetyl-p-aminophenylserinol + reduced acceptor + 2 O2 = chloramphenicol + acceptor + 2 H2O

Glossary: α-N-dichloroacetyl-p-aminophenylserinol = N-[(1R,2R)-1-(4-aminophenyl)-1,3-dihydroxypropan-2-yl]-2,2-dichloroacetamide

Other name(s): cmlI (gene name)

Systematic name: α-N-dichloroacetyl-p-aminophenylserinol,acceptor:oxygen oxidoreductase (N-hydroxylating)

Comments: The enzyme, isolated from the bacterium Streptomyces venezuelae, is involved in the biosynthesis of the antibiotic chloramphenicol. It contains a carboxylate-bridged binuclear non-heme iron cluster. The components of the native electron chain have not been identified, although the immediate donor is likely to be an iron-sulfur protein. The reaction mechanism involves formation of an extremely stable peroxo intermediate that catalyses three individual two-electron oxidations via a hydroxylamine and a nitroso intermediates without releasing the intermediates. cf. 68.html, 4-aminobenzoate N-oxygenase.

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


1. Lu, H., Chanco, E. and Zhao, H. CmlI is an N-oxygenase in the biosynthesis of chloramphenicol. Tetrahedron 68 (2012) 7651-7654. [PMID: 24347692]

2. Makris, T.M., Vu, V.V., Meier, K.K., Komor, A.J., Rivard, B.S., Munck, E., Que, L., Jr. and Lipscomb, J.D. An unusual peroxo intermediate of the arylamine oxygenase of the chloramphenicol biosynthetic pathway. J. Am. Chem. Soc. 137 (2015) 1608-1617. [PMID: 25564306]

3. Komor, A.J., Rivard, B.S., Fan, R., Guo, Y., Que, L., Jr. and Lipscomb, J.D. CmlI N-oxygenase catalyzes the final three steps in chloramphenicol biosynthesis without dissociation of intermediates. Biochemistry 56 (2017) 4940-4950. [PMID: 28823151]

[EC created 2020]

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