ATP synthesis with single turnover flashes in spinach chloroplasts

[摘要]

Single-turnover flash-induced ATP synthesis in chloroplasts was measured in situ with the luciferin luminescence method. In dark-adapted chloroplasts the first flashes only induce ATP hydrolysis. Once the reversible ATPase is fully activated, ATP hydrolysis persists for extended periods of darkness and flash-induced ATP-synthesis is optimal even at flash frequencies lower than 0.1 Hz. About one molecule of ATP is formed per 1000 chlorophyll and flash. In a low frequency flashing regime under steady state conditions, the newly formed ATP is stable. There is no threshold light intensity for flash-induced ATP synthesis. The data are in agreement with models involving short-range interaction between electron transport and the coupling factor.

[学科分类] 生物化学/生物物理

[关键词] ATP synthesis;ATP hydrolysis;Single-turnover flash;Thylakoidal ATPase;Coupling mechanism;Hepes;N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid;Tris;tris-(hydroxymethyl)-aminomethane;DCCD;N;N′-dicyclohexylcarbodiimide;TNBT;tri-n-butyltin;CF1;chloroplast coupling factor;chl;chlorophyll