title: Free fatty acids decouple oxidative phosphorylation by dissipating intramembranal protons without inhibiting ATP synthesis driven by the proton electrochemical gradient.
abstract: Free fatty acids (FFA) uncouple oxidative phosphorylation and reverse electron transport and inhibit ATP-Pi exchange in beef heart submitochondrial particles. In this, they resemble classical uncouplers and ionophores. However, in contrast to the latter agents, FFA do not collapse the substrate generated proton electrochemical potential and do not inhibit ATP synthesis when the latter is driven by artificially imposed delta microH. These results lend further support to the suggestion that oxidative phosphorylation depends, in part, on direct intramembranal proton transfer - a process which is specifically uncoupled by FFA and other membrane perturbing agents (e.g. general anesthetics).
authors.forename: H
authors.initials: H
authors.lastname: Rottenberg
authors.forename: S
authors.initials: S
authors.lastname: Steiner-Mordoch
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D000818:Animals; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002417:Cattle; D004579:Electron Transport; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D009206:Myocardium / Q000648:ultrastructure; D010085:Oxidative Phosphorylation; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D013367:Submitochondrial Particles / Q000378:metabolism; D013696:Temperature
chemical_list: D005230:Fatty Acids, Nonesterified; D010169:Palmitic Acids; D019308:Palmitic Acid; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases