IUBMB Enzyme Nomenclature


Accepted name: fenbendazole monooxygenase (4'-hydroxylating)

Reaction: fenbendazole + [reduced NADPH—hemoprotein reductase] + O2 = 4'-hydroxyfenbendazole + [oxidized NADPH—hemoprotein reductase] + H2O

For diagram of reaction click here.

Glossary: fenbendazole = methyl [5-(phenylsulfanyl)-1H-benzimidazol-2-yl]carbamate
4'-hydroxyfenbendazole = methyl [5-(4-hydroxyphenylsulfanyl)-1H-benzimidazol-2-yl]carbamate
albendazole = methyl [5-(propylsulfanyl)-1H-benzimidazol-2-yl]carbamate

Other name(s): CYP2C19 (gene name)

Systematic name: fenbendazole,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (4'-hydroxylating)

Comments: CYP2C19 is microsomal cytochrome P-450 monooxygenase that catalyses the hydroxylation of the benzene ring of fenbendazole, a broad-spectrum anthelmintic used against gastrointestinal nematodes and the larval stages of cestodes. This activity is also carried out by CYP2J2. cf. EC, albendazole monooxygenase (hydroxylating). CYP2C19 does not act on albendazole.

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


1. Wu, Z., Lee, D., Joo, J., Shin, J.H., Kang, W., Oh, S., Lee, D.Y., Lee, S.J., Yea, S.S., Lee, H.S., Lee, T. and Liu, K.H. CYP2J2 and CYP2C19 are the major enzymes responsible for metabolism of albendazole and fenbendazole in human liver microsomes and recombinant P450 assay systems. Antimicrob. Agents Chemother. 57 (2013) 5448-5456. [PMID: 23959307]

[EC created 2018]

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