"Caffeine synthase gene from tea leaves"
/ Misako Kato, Kouichi Mizuno, Alan Crozier, Tatsuhito Fujimura and Hiroshi Ashihara*
/ Nature
/ Volume 406
/ August 31, 2000
... There was no 7-N-methylation activity when...
http://www.biotech-info.net/caffeine_synthase.html