Reactivation of photosynthetic oxygen evolution in tris-inactivated inside-out photosystem II vesicles from spinach

Modification of oxygen evolving center by Tris-washing

Tris-washing inhibits the O2-evolving center of chloroplasts and their particles specifically and reversibly, and it was applied to many investigations on O2-evolving center and PS II reaction center. In this review are introduced the various photosynthetic investigations in which Tris-washing was applied and are also discussed briefly on the site and the mechanism of Tris-inactivation, properties of P680 and Z, characteristic change in fluorescence and delayed light emission, and reactivation of O2-evolving center by DCPIP.H2-treatment and photo-reactivation of Tris-washed chloroplasts and their particles.

EDTA-induced release of manganese and proteins from inside-out thylakoid vesicles and the inhibition of oxygen evolution

Washing of inside-out, but not right-way-round, pea chloroplast thylakoid vesicles with 2 mM EDTA inhibits O2 evolution. Artificial electron donor/acceptor studies indicate that the site of inhibition is on the oxidising side of photosystem two (PS2), a conclusion reinforced by chlorophyll fluorescence measurements. Evidence is presented that the EDTA inhibition of O2 evolution is linked partly to the removal of one Mn atom per PS2 reaction centre and partly to the removal of extrinsic membrane proteins having apparent molecular weights between 58 and 70 kdaltons.