IUBMB Enzyme Nomenclature


Accepted name: caffeine synthase

Reaction: (1) S-adenosyl-L-methionine + 3,7-dimethylxanthine = S-adenosyl-L-homocysteine + 1,3,7-trimethylxanthine
(2) S-adenosyl-L-methionine + 1,7-dimethylxanthine = S-adenosyl-L-homocysteine + 1,3,7-trimethylxanthine
(3) S-adenosyl-L-methionine + 7-methylxanthine = S-adenosyl-L-homocysteine + 3,7-dimethylxanthine

For diagram of reaction click here

Glossary: theobromine = 3,7-dimethylxanthine
paraxanthine = 1,7-dimethylxanthine
caffeine = 1,3,7-trimethylxanthine

Other name(s): dimethylxanthine methyltransferase, 3N-methyltransferase; DXMT; CCS1; S-adenosyl-L-methionine:3,7-dimethylxanthine 1-N-methyltransferase

Systematic name: S-adenosyl-L-methionine:3,7-dimethylxanthine N1-methyltransferase

Comments: Paraxanthine is the best substrate for this enzyme but the paraxanthine pathway is considered to be a minor pathway for caffeine biosynthesis [2,3].

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


1. Kato, M., Mizuno, K., Fujimura, T., Iwama, M., Irie, M., Crozier, A. and Ashihara, H. Purification and characterization of caffeine synthase from tea leaves. Plant Physiol. 120 (1999) 579-586. [PMID: 10364410]

2. Mizuno, K., Okuda, A., Kato, M., Yoneyama, N., Tanaka, H., Ashihara, H. and Fujimura, T. Isolation of a new dual-functional caffeine synthase gene encoding an enzyme for the conversion of 7-methylxanthine to caffeine from coffee (Coffea arabica L.). FEBS Lett. 534 (2003) 75-81. [PMID: 12527364]

3. Uefuji, H., Ogita, S., Yamaguchi, Y., Koizumi, N. and Sano, H. Molecular cloning and functional characterization of three distinct N-methyltransferases involved in the caffeine biosynthetic pathway in coffee plants. Plant Physiol. 132 (2003) 372-380. [PMID: 12746542]

4. Kato, M., Mizuno, K., Crozier, A., Fujimura, T. and Ashihara, H. Caffeine synthase gene from tea leaves. Nature 406 (2000) 956-957. [PMID: 10984041]

[EC created 2007]

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