IUBMB Enzyme Nomenclature


Accepted name: rifampicin monooxygenase

Reaction: rifampicin + NAD(P)H + O2 = 2-hydroxyrifampicin + NAD(P)+ + H2O

For diagram of reaction click here

Glossary: rifampicin = (2S,12Z,14E,16S,17S,18R,19R,20R,21S,22R,23S,24E)-5,6,9,17,19-pentahydroxy-23-methoxy-2,4,12,16,18,20,22-heptamethyl-8-{[(E)-(4-methylpiperazin-1-yl)imino]methyl}-1,11-dioxo-1,2-dihydro-2,7-(epoxypentadeca-1,11,13-trienoimino)nathpho[2,1-b]furan-21-yl acetate

Other name(s): RIF-O; ROX; RIFMO; rifampicin:NAD(P)H:oxygen oxidoreductase (2'-N-hydroxyrifampicin-forming) (incorrect)

Systematic name: rifampicin:NAD(P)H:oxygen oxidoreductase (C2-hydroxyrifampicin-forming; ring-cleaving)

Comments: The enzyme has been found in a variety of environmental bacteria, notably Rhodococcus, Nocardia, and Streptomyces. It hydroxylates C-2 of rifampicin leading to its macro-ring cleaving.

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


1. Andersen, S.J., Quan, S., Gowan, B. and Dabbs, E.R. Monooxygenase-like sequence of a Rhodococcus equi gene conferring increased resistance to rifampin by inactivating this antibiotic. Antimicrob. Agents Chemother. 41 (1997) 218-221. [PMID: 8980786]

2. Hoshino, Y., Fujii, S., Shinonaga, H., Arai, K., Saito, F., Fukai, T., Satoh, H., Miyazaki, Y. and Ishikawa, J. Monooxygenation of rifampicin catalyzed by the rox gene product of Nocardia farcinica: structure elucidation, gene identification and role in drug resistance. J. Antibiot. (Tokyo) 63 (2010) 23-28. [PMID: 19942945]

3. Koteva, K., Cox, G., Kelso, J.K., Surette, M.D., Zubyk, H.L., Ejim, L., Stogios, P., Savchenko, A., Sørensen, D. and Wright, G.D. Rox, a rifamycin resistance enzyme with an unprecedented mechanism of action. Cell Chem Biol 25 (2018) 403-412.e5. [PMID: 29398560]

4. Liu, L.K., Dai, Y., Abdelwahab, H., Sobrado, P. and Tanner, J.J. Structural evidence for rifampicin monooxygenase inactivating rifampicin by cleaving Its ansa-bridge. Biochemistry 57 (2018) 2065-2068. [PMID: 29578336]

[EC created 2016, modified 2022]

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