Photosynthetic Electron Transport Inhibition By Pyrones and Pyridones: Structure-Activity Relationships

Abstract

The 4-pyrone and 4-pyridone series were examined as a new type of photosynthetic inhibitor because of a structural resemblance to the co-enzyme plastoquinone, which lies between photosystem II and cytochrome b. These compounds inhibited a Hill reaction at "the plastoquinone pool." From our study of the structure/activity relationships for 4-pyrones and 4-pyridones, it has become clear that these compounds need no strict structural resemblance to the plastoquinone. It is also demonstrated that the brominated 4-pyridone series has remarkably higher inhibitory activities than those of its non brominated analogues.