The phosphate potential maintained by mitochondria in State 4 is proportional to the proton-motive force.
Evidence is presented for a proportional relationship between the extramitochondrial phosphate potential (delta Gexp) and the proton-motive force (delta mu H+) across the mitochondrial membrane in rat-liver mitochondria oxidising succinate in State 4, when delta mu H+ is varied by addition of uncouplers or malonate. This relationship was found when precautions were taken to minimise interference with the determination of delta Gexp and delta mu H+ by intramitochondrial nucleotides, adenylate kinase activity, the quenching method, and delta mu H+-dependent changes in matrix volume. A non-proportional delta Gexp/delta mu H+ relationship was obtained when these precautions were omitted. Our results do not support mosaic protonic coupling, but are not necessarily in conflict with other localised coupling schemes.
Woelders
H
H
van der Zande
W J
WJ
Colen
A M
AM
Wanders
R J
RJ
van Dam
K
K
D000227:Adenine Nucleotides / Q000378:metabolism; D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D004563:Electrochemistry; D004734:Energy Metabolism; D007425:Intracellular Membranes / Q000502:physiology; D008314:Malonates / Q000494:pharmacology; D008930:Mitochondria, Liver / Q000187:drug effects / Q000502:physiology*; D010084:Oxidation-Reduction; D010710:Phosphates / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D011522:Protons; D051381:Rats; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid; D014475:Uncoupling Agents / Q000494:pharmacology
D000227:Adenine Nucleotides; D008314:Malonates; D010710:Phosphates; D011522:Protons; D013386:Succinates; D014475:Uncoupling Agents; C030290:malonic acid; D019802:Succinic Acid; D000263:Adenylate Kinase; D011188:Potassium