IUBMB Enzyme Nomenclature


Accepted name: methylxanthine N3-demethylase

Reaction: (1) theobromine + O2 + NAD(P)H + H+ = 7-methylxanthine + NAD(P)+ + H2O + formaldehyde
(2) 3-methylxanthine + O2 + NAD(P)H + H+ = xanthine + NAD(P)+ + H2O + formaldehyde

Glossary: theobromine = 3,7-dimethylxanthine

Other name(s): ndmB (gene name)

Systematic name: theobromine:oxygen oxidoreductase (N3-demethylating)

Comments: A non-heme iron oxygenase. The enzyme from the bacterium Pseudomonas putida shares an NAD(P)H-FMN reductase subunit with EC, methylxanthine N1-demethylase, and has higher activity with NADH than with NADPH [1]. Also demethylates caffeine and theophylline with lower efficiency. Forms part of the degradation pathway of methylxanthines.

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


1. Summers, R.M., Louie, T.M., Yu, C.L. and Subramanian, M. Characterization of a broad-specificity non-haem iron N-demethylase from Pseudomonas putida CBB5 capable of utilizing several purine alkaloids as sole carbon and nitrogen source. Microbiology 157 (2011) 583-592. [PMID: 20966097]

2. Summers, R.M., Louie, T.M., Yu, C.L., Gakhar, L., Louie, K.C. and Subramanian, M. Novel, highly specific N-demethylases enable bacteria to live on caffeine and related purine alkaloids. J. Bacteriol. 194 (2012) 2041-2049. [PMID: 22328667]

[EC created 2013]

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