Photochemical reaction sequences of blue light activated flavins: sensory transduction through free radical messengers.

Flavin photochemistry involves the production of transient flavin free radicals which in turn sensitize molecular oxygen to generate superoxide. The blue light induced photochemical chain reaction of flavins may be blocked at two different levels by photoresponse inhibitors. A protein-bound/lipid-bound flavin located on the biomembrane may take part in the blue-light mediated sensory transduction by 'releasing' a 'free radical messenger' equivalent into the cell interior.