Properties of ATP-induced chlorophyll luminescence in chloroplasts.
1. The recently described reaction of ATP-induced luminescence is analyzed for its relation to other ATP-induced reactions such as ATP-driven transmembrane proton gradient formation and ATP-driven reverse electron flow. 2. In the absence of phenazine methosulfate ATP-induced luminescence is optimal while the main phase of ATP-driven reverse electron flow is eliminated. 3. DCMU which by itself causes a much smaller luminescence, inhibits the ATP-induced luminescence. 4. Nigericin plus valinomycin, but not each by itself, fully inhibit the ATP-induced luminescence. 5. The observations are interpreted as indicating that ATP stimulates luminescence by a 2-fold mechanism: (a) increasing the amount of the reducing primary electron acceptor of Photosystem II, Q, and (b) creating a transmembrane electrochemical potential which serves to decrease the activation energy required for the charge recombination reaction which leads to luminescence.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D004227:Dithionite / Q000494:pharmacology; D004237:Diuron / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D007700:Kinetics; D008163:Luminescent Measurements; D008773:Methylphenazonium Methosulfate / Q000494:pharmacology; D009550:Nigericin / Q000494:pharmacology; D010944:Plants; D014634:Valinomycin / Q000494:pharmacology
D002734:Chlorophyll; D004227:Dithionite; D014634:Valinomycin; D008773:Methylphenazonium Methosulfate; D000255:Adenosine Triphosphate; D004237:Diuron; D000251:Adenosine Triphosphatases; D009550:Nigericin