Partial Resolution of the Enzymes Catalyzing Photophosphorylation

Extraction of chloroplasts with cholate yielded a fraction which contained chloroplast coupling factor 1, lipids, and other proteins, but was depleted in chlorophyll and cytochromes.Dialysis of the cholate extract reconstituted a vesicular preparation which catalyzed Pi-ATP exchange and ATPase activities.2. The Pi-ATP exchange activity was inhibited by uncouplers of photophosphorylation such as gramicidin or atebrin and by energy transfer inhibitors such as DIO-9 or N', N'-dicyclohexylcarbodiimide.Both Pi-ATP exchange and ATPase activities were also inhibited by an antiserum against chloroplast coupling factor 1.3. An ammonium sulfate fraction obtained from the cholate extract also catalyzed Pi-ATP exchange which was, however, insensitive to uncouplers.