IUBMB Enzyme Nomenclature


Accepted name: tetracycline 11a-monooxygenase

Reaction: tetracycline + NADPH + H+ + O2 = 11a-hydroxytetracycline + NADP+ + H2O

For diagram of reaction click here.

Other name(s): tetX (gene name)

Systematic name: tetracycline,NADPH:oxygen oxidoreductase (11a-hydroxylating)

Comments: A flavoprotein (FAD). This bacterial enzyme confers resistance to all clinically relevant tetracyclines when expressed under aerobic conditions. The hydroxylated products are very unstable and lead to intramolecular cyclization and non-enzymic breakdown to undefined products.

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


1. Yang, W., Moore, I.F., Koteva, K.P., Bareich, D.C., Hughes, D.W. and Wright, G.D. TetX is a flavin-dependent monooxygenase conferring resistance to tetracycline antibiotics. J. Biol. Chem. 279 (2004) 52346-52352. [PMID: 15452119]

2. Moore, I.F., Hughes, D.W. and Wright, G.D. Tigecycline is modified by the flavin-dependent monooxygenase TetX. Biochemistry 44 (2005) 11829-11835. [PMID: 16128584]

3. Volkers, G., Palm, G.J., Weiss, M.S., Wright, G.D. and Hinrichs, W. Structural basis for a new tetracycline resistance mechanism relying on the TetX monooxygenase. FEBS Lett. 585 (2011) 1061-1066. [PMID: 21402075]

[EC created 2016]

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