The Enzyme Database

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EC 1.14.13.178     
Accepted name: methylxanthine N1-demethylase
Reaction: (1) caffeine + O2 + NAD(P)H + H+ = theobromine + NAD(P)+ + H2O + formaldehyde
(2) theophylline + O2 + NAD(P)H + H+ = 3-methylxanthine + NAD(P)+ + H2O + formaldehyde
(3) paraxanthine + O2 + NAD(P)H + H+ = 7-methylxanthine + NAD(P)+ + H2O + formaldehyde
Glossary: caffeine = 1,3,7-trimethylxanthine
theobromine = 3,7-dimethylxanthine
theophylline = 1,3-dimethylxanthine
paraxanthine = 1,7-dimethylxanthine
Other name(s): ndmA (gene name)
Systematic name: caffeine:oxygen oxidoreductase (N1-demethylating)
Comments: A non-heme iron oxygenase. The enzyme from the bacterium Pseudomonas putida shares an NAD(P)H-FMN reductase subunit with EC 1.14.13.179, methylxanthine N3-demethylase, and has a 5-fold higher activity with NADH than with NADPH [2]. Also demethylate 1-methylxantine with lower efficiency. Forms part of the degradation pathway of methylxanthines.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
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. [DOI] [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. [DOI] [PMID: 22328667]
[EC 1.14.13.178 created 2013]
 
 
EC 2.1.1.159     
Accepted name: theobromine synthase
Reaction: S-adenosyl-L-methionine + 7-methylxanthine = S-adenosyl-L-homocysteine + 3,7-dimethylxanthine
For diagram of caffeine biosynthesis, click here
Glossary: theobromine = 3,7-dimethylxanthine
paraxanthine = 1,7-dimethylxanthine
Other name(s): monomethylxanthine methyltransferase; MXMT; CTS1; CTS2; S-adenosyl-L-methionine:7-methylxanthine 3-N-methyltransferase
Systematic name: S-adenosyl-L-methionine:7-methylxanthine N3-methyltransferase
Comments: This is the third enzyme in the caffeine-biosynthesis pathway. This enzyme can also catalyse the conversion of paraxanthine into caffeine, although the paraxanthine pathway is considered to be a minor pathway for caffeine biosynthesis [2,3].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Ogawa, M., Herai, Y., Koizumi, N., Kusano, T. and Sano, H. 7-Methylxanthine methyltransferase of coffee plants. Gene isolation and enzymatic properties. J. Biol. Chem. 276 (2001) 8213–8218. [DOI] [PMID: 11108716]
2.  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. [DOI] [PMID: 12746542]
3.  Yoneyama, N., Morimoto, H., Ye, C.X., Ashihara, H., Mizuno, K. and Kato, M. Substrate specificity of N-methyltransferase involved in purine alkaloids synthesis is dependent upon one amino acid residue of the enzyme. Mol. Genet. Genomics 275 (2006) 125–135. [DOI] [PMID: 16333668]
[EC 2.1.1.159 created 2007]
 
 
EC 2.1.1.160     
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 caffeine biosynthesis, 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
References:
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. [DOI] [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. [DOI] [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. [DOI] [PMID: 10984041]
[EC 2.1.1.160 created 2007]
 
 


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