Inorganic pyrophosphate‐driven ATP‐synthesis in liposomes containing membrane‐bound inorganic pyrophosphatase and F0‐F1 complex from Rhodospirillum rubrum

Abstract

PP1 driven ATP synthesis has been reconstituted in a liposomal system containing the membrane-bound energy-linked PP1ase and coupling factor complex, both highly purified from Rhodospirillum rubrum. This energy converting model system was made by mixing both enzyme preparations with an aqueous suspension of sonicated soybean phospholipids and subjecting to a freeze—thaw procedure. In the presence of ADP, Mg2+, P1 and PP1 the system catalyzed phosphorylation by up to 25 nmol ATP formed X mg protein−1 X min−1, at 20°C, which was sensitive to uncouplers and inhibitors of phosphorylation such as oligomycin, efrapeptin and N,N′-dicyclohexylcarbodiimide