Caffeine synthase

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:


 * 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; the Coffea species arabica, and canephora; and in Theobroma cacao.