Caffeine synthase

Template:Short description Template:Infobox enzyme 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.