Conjeaud H, Mathis P
Biochim Biophys Acta. 1980 May 9;590(3):353-9. doi: 10.1016/0005-2728(80)90206-6.
The primary donor of Photosystem II (PS II), P-680, was photo-oxidized by a short flash and its rate of reduction was measured at different pH values by following the recovery of the absorption change at 820 nm in chloroplasts pretreated with a high concentration of Tris. The re-duction is biphasic with a fast phase (dominant after the first flash) attributed to the donation by a donor, D1, and a slow phase (usually dominant after the second flash) attributed to a back-reaction with the primary acceptor. It is found that pH has a strong influence on the donation from D1 (PI = 2 MICROSECONDS AT PH 9, 44 microseconds at pH 4), but no influence on the back reaction (pi approximately 200 microseconds). pH also influences the stability of the charge separation since the contribution of donation from D1 at the second flash increases at lower pH, getting close to 100% at pH 4.
光系统II（PS II）的主要供体P-680被短闪光光氧化，通过追踪用高浓度Tris预处理的叶绿体中820 nm处吸收变化的恢复情况，在不同pH值下测量其还原速率。还原是双相的，快速相（第一次闪光后占主导）归因于供体D1的供体作用，慢速相（通常在第二次闪光后占主导）归因于与初级受体的反向反应。研究发现，pH对D1的供体作用有强烈影响（pH为9时PI = 2微秒，pH为4时为44微秒），但对反向反应没有影响（pi约为200微秒）。pH还影响电荷分离的稳定性，因为第二次闪光时D1供体作用的贡献在较低pH下增加，在pH为4时接近100%。
