Caffeine synthase explained

Caffeine synthase
Ec Number:	2.1.1.160
Cas Number:	155215-94-4

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]

\rightleftharpoons S-adenosyl-L-homocysteine + caffeine + H⁺\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]

Notes and References

1. Kato M, Mizuno K, Fujimura T, Iwama M, Irie M, Crozier A, Ashihara H . Purification and characterization of caffeine synthase from tea leaves . Plant Physiol. . 120 . 2 . 579–86 . June 1999 . 10364410 . 59297 . 10.1104/pp.120.2.579.
2. Kato M, Mizuno K, Crozier A, Fujimura T, Ashihara H . Caffeine synthase gene from tea leaves . Nature . 406 . 6799 . 956–7 . August 2000 . 10984041 . 10.1038/35023072 .
3. Mizuno K, Okuda A, Kato M, Yoneyama N, Tanaka H, Ashihara H, 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 . 1–3 . 75–81 . January 2003 . 12527364 . 10.1016/S0014-5793(02)03781-X. free .
4. Uefuji H, Ogita S, Yamaguchi Y, Koizumi N, Sano H . 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 . May 2003 . 12746542 . 166982 . 10.1104/pp.102.019679 .
5. McCarthy AA, Biget L, Lin C, Petiard V, Tanksley SD, McCarthy JG . Cloning, expression, crystallization and preliminary X-ray analysis of the XMT and DXMT N-methyltransferases from Coffea canephora (robusta) . Acta Crystallographica Section F . 63 . Pt 4 . 304–7 . April 2007 . 17401201 . 2330209 . 10.1107/S1744309107009268 .
6. Yoneyama N, Morimoto H, Ye CX, Ashihara H, Mizuno K, 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 . 2 . 125–35 . February 2006 . 16333668 . 10.1007/s00438-005-0070-z .