The Photoresponse of S-Adenosylmethionine Decarboxylase Activity in Leaves of Pharbitis nil

S-Adenosylmethionine decarboxylase activity in leaves of Pharbitisnil increased dramatically at lights-on and then gradually decreasedin the light. The enzymatic activity fell dramatically at lights-offthen increased slightly in darkness. Photoinduction was preventedby cycloheximide and the enzymatic activity fell dramaticallyupon treatment with cycloheximide in the light. ¹Present address: Sakuya Konohana Kan, Osaka City Parks Association,Tsurumi-ku, Osaka, 538 Japan