PROTOCHLOROPHYLLIDE REDUCTASE .3. SYNTHESIS OF A PROTOCHLOROPHYLLIDE-DIHYDROFLAVIN COMPLEX

A mild and efficient method of linking a dihydroflavin to the C-17 car boxylic acid side chain of protochlorophyllide, without degradation of the sensitive E ring or loss of magnesium, is described. The appended dihydroflavin was shown to quench the fluorescence of protochlorophyl lide. In contrast, a dihydronicotinamide moiety was unable to effect f luorescence quenching. The relevance of these findings to a possible m echanism of action of the enzyme protochlorophyllide reductase is disc ussed.