INHIBITION OF PLANT ORNITHINE AMINOTRANSFERASE BY GABACULINE AND 4-AMINO-5-HEXYNOIC ACID

Gabaculine (GAB) and 4-amino-5-hexynoic acid (AHA) have been shown to be enzyme-activated inhibitors of radish ornithine aminotransferase (O AT). The in vitro results were entirely compatible with the in vivo si tuation. However, it appeared that GAB was a more effective inhibitor than AHA as it was active at a lower concentration (1 muM) leading in vivo to almost complete irreversible inhibition of OAT within a few ho urs. GAB and AHA will be useful tools to study the physiological conse quences of OAT inhibition in plants.