Synthesis of adenosine triphosphate by an artificially imposed electrochemical proton gradient in bovine heart submitochondrial particles.
Submitochondrial particles subjected to an artificially imposed electrochemical proton gradient consisting of a pH gradient (acid to base transition) and membrane potential (low to high K-+ transition in the presence of valinomycin) catalyzed the net synthesis of 2.5 nmol of [-32P]ATP per mg of protein from ADP and 32-Pi.  Optimal reaction conditions included incubation of submitochondrial particles in malonate at pH 5.0 with valinomycin in the absence of added K-+, followed by a rapid transition to pH 7.5 and 100 mM K-+.  ATP synthesis continued for about 6 s and was sensitive to uncouplers or oligomycin but insensitive to inhibitors of electron transport.  Lower amounts of ATP were formed by either the pH gradient (25%) of K-+ gradient (15%) alone.  These results demonstrate that an electrochemical gradient of protons can drive the synthesis of ATP by reversal of the proton-translocating ATPase independent of electron transport.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D002417:Cattle; D002951:Citrates / Q000494:pharmacology; D003486:Cyanides / Q000494:pharmacology; D004227:Dithionite / Q000494:pharmacology; D004579:Electron Transport; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008293:Malates / Q000494:pharmacology; D008298:Maleates / Q000494:pharmacology; D008314:Malonates / Q000494:pharmacology; D008564:Membrane Potentials; D008931:Mitochondria, Muscle / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D010086:Oxidative Phosphorylation Coupling Factors / Q000494:pharmacology; D010710:Phosphates / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D011188:Potassium / Q000494:pharmacology; D011522:Protons; D012402:Rotenone / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
D002951:Citrates; D003486:Cyanides; D008293:Malates; D008298:Maleates; D008314:Malonates; D010086:Oxidative Phosphorylation Coupling Factors; D010710:Phosphates; D010761:Phosphorus Radioisotopes; D011522:Protons; D012402:Rotenone; D004227:Dithionite; D014634:Valinomycin; D000968:Antimycin A; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D011188:Potassium