Caffeine synthase

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Caffeine synthase is a methyltransferase enzyme involved in the caffeine biosynthesis pathway. It is expressed in tea species, coffee species, and cocoa species. The enzyme catalyses the following reactions:^[1]

S-adenosyl-L-methionine + theobromine $\rightleftharpoons$ S-adenosyl-L-homocysteine + caffeine + H⁺
S-adenosyl-L-methionine + paraxanthine $\rightleftharpoons$ S-adenosyl-L-homocysteine + caffeine + H⁺
7-methylxanthine + S-adenosyl-L-methionine $\rightleftharpoons$ S-adenosyl-L-homocysteine + H⁺ + theobromine

Caffeine synthase is expressed in the Camellia species irrawadiensis, ptilophylla, and sinensis;^[2] the Coffea species arabica,^[3]^[4] and canephora;^[5] and in Theobroma cacao.^[6]

References

↑ Kato M, Mizuno K, Fujimura T, Iwama M, Irie M, Crozier A, Ashihara H (June 1999). "Purification and characterization of caffeine synthase from tea leaves". Plant Physiol. 120 (2): 579–86. doi:10.1104/pp.120.2.579. PMC 59297. PMID 10364410.
↑ Kato M, Mizuno K, Crozier A, Fujimura T, Ashihara H (August 2000). "Caffeine synthase gene from tea leaves". Nature. 406 (6799): 956–7. doi:10.1038/35023072. PMID 10984041.
↑ Mizuno K, Okuda A, Kato M, Yoneyama N, Tanaka H, Ashihara H, Fujimura T (January 2003). "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 (1-3): 75–81. doi:10.1016/S0014-5793(02)03781-X. PMID 12527364.
↑ Uefuji H, Ogita S, Yamaguchi Y, Koizumi N, Sano H (May 2003). "Molecular cloning and functional characterization of three distinct N-methyltransferases involved in the caffeine biosynthetic pathway in coffee plants". Plant Physiol. 132 (1): 372–80. doi:10.1104/pp.102.019679. PMC 166982. PMID 12746542.
↑ McCarthy AA, Biget L, Lin C, Petiard V, Tanksley SD, McCarthy JG (April 2007). "Cloning, expression, crystallization and preliminary X-ray analysis of the XMT and DXMT N-methyltransferases from Coffea canephora (robusta)". Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 63 (Pt 4): 304–7. doi:10.1107/S1744309107009268. PMC 2330209. PMID 17401201.
↑ Yoneyama N, Morimoto H, Ye CX, Ashihara H, Mizuno K, Kato M (February 2006). "Substrate specificity of N-methyltransferase involved in purine alkaloids synthesis is dependent upon one amino acid residue of the enzyme". Mol. Genet. Genomics. 275 (2): 125–35. doi:10.1007/s00438-005-0070-z. PMID 16333668.

Transferase: one carbon transferases (EC 2.1)

2.1.1: Methyl-

N-	Histamine N-methyltransferase Phenylethanolamine N-methyltransferase Amine N-methyltransferase Phosphatidylethanolamine N-methyltransferase

O-	5-hydroxyindole-O-methyltransferase/Acetylserotonin O-methyltransferase Catechol-O-methyl transferase

Homocysteine	Betaine-homocysteine methyltransferase Homocysteine methyltransferase Methionine synthase

Other	Phosphatidyl ethanolamine methyltransferase DNMT3B Histone methyltransferase Thymidylate synthase DNA methyltransferase Thiopurine methyltransferase

2.1.2: Hydroxymethyl-,
Formyl- and Related

Hydroxymethyltransferase	Serine hydroxymethyltransferase 3-methyl-2-oxobutanoate hydroxymethyltransferase

Formyltransferase	Phosphoribosylglycinamide formyltransferase Inosine monophosphate synthase

Other	Glutamate formimidoyltransferase Aminomethyltransferase

2.1.3: Carboxy-
and Carbamoyl

Carboxy	methylmalonyl-CoA carboxytransferase

Carbamoyl	Aspartate carbamoyltransferase Ornithine carbamoyltransferase Oxamate carbamoyltransferase Putrescine carbamoyltransferase 3-hydroxymethylcephem carbamoyltransferase Lysine carbamoyltransferase N-acetylornithine carbamoyltransferase

2.1.4: Amidine

Arginine:glycine amidinotransferase

Enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list)

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