We report the first reasonable model for the active site of the membrane‐bound aromatic prenyltransferase UbiA, derived from structural—not sequence—similarity to a terpene synthase, with the aid of threading, site‐directed mutagenesis, and substrate selectivities. The high similarity of the active fold of UbiA‐transferase to that of 5‐epi‐aristolochene synthase (Nictotiana tabacum ), despite a low homology, allows a hypothesis on a convergent evolution of these enzymes to be formed.

For the first time a member of the CYP74 enzyme subfamily (9‐AOS) from tomato has been shown by chemical and analytical approaches to catalyze multiple reactions. These multifunctional properties of 9‐AOS from the oxylipin‐forming lipoxygenase (LOX) pathway raise several new questions on lipid‐derived signaling.

We report the first reasonable model for the active site of the membrane‐bound aromatic prenyltransferase UbiA, derived from structural—not sequence—similarity to a terpene synthase, with the aid of threading, site‐directed mutagenesis, and substrate selectivities. The high similarity of the active fold of UbiA‐transferase to that of 5‐epi‐aristolochene synthase (Nictotiana tabacum ), despite a low homology, allows a hypothesis on a convergent evolution of these enzymes to be formed.

For the first time a member of the CYP74 enzyme subfamily (9‐AOS) from tomato has been shown by chemical and analytical approaches to catalyze multiple reactions. These multifunctional properties of 9‐AOS from the oxylipin‐forming lipoxygenase (LOX) pathway raise several new questions on lipid‐derived signaling.

For the first time a member of the CYP74 enzyme subfamily (9‐AOS) from tomato has been shown by chemical and analytical approaches to catalyze multiple reactions. These multifunctional properties of 9‐AOS from the oxylipin‐forming lipoxygenase (LOX) pathway raise several new questions on lipid‐derived signaling.

We report the first reasonable model for the active site of the membrane‐bound aromatic prenyltransferase UbiA, derived from structural—not sequence—similarity to a terpene synthase, with the aid of threading, site‐directed mutagenesis, and substrate selectivities. The high similarity of the active fold of UbiA‐transferase to that of 5‐epi‐aristolochene synthase (Nictotiana tabacum ), despite a low homology, allows a hypothesis on a convergent evolution of these enzymes to be formed.