7-Deoxy-sedoheptulose is a cyanobacterial antimetabolite of the 3-dehydroquinate synthase, second enzyme of the shikimatepathway. Design of a hybridsynthesis of chemical and chemoenzymatic steps using heterologously expressed transketolase efficiently yielded the heptulose family. In vivo and in vitro studies on Anabaena variabilis and Arabidopsis thaliana gave a profound understanding of the mode