Relationship of potassium ion transport and ATP synthesis in pea cotyledon mitochondria.
Simultaneous monitoring of ATP synthesis and K+ movements across pea mitochondrial membranes revealed information about the competition of the two processes for mitochondrial energy. In the presence of valinomycin and at low extramitochondrial K+ concentration, ADP could be phosphorylated rapidly. This occurred with a decrease in net potassium ion uptake. At higher external K+ concentrations respiratory energy was unavailable for ATP synthesis and only a portion of added ADP could be phosphorylated within a reasonable time. Magnesium ions were shown to have an inhibitor effect on the K+ uptake, and stimulated a greater rate of ATP synthesis. When valinomycin and ADP were added simultaneously so that phosphorylation of the ADP and enhancement of K+ uptake could complete for mitochondrial energy, K+ uptake was preferred over ATP synthesis.
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D001693:Biological Transport, Active; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D010085:Oxidative Phosphorylation / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects; D010944:Plants / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
D014634:Valinomycin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D008274:Magnesium; D011188:Potassium