Inactivation of Photosynthetic Oxygen Evolution and Concomitant Release of Three Polypeptides in the Photosystem II Particles of Spinach Chloroplasts

摘要

Photosystem II particles having an oxygen evolution activity as high as 300μmol mg−1chlorophyll hr−1were prepared from spinach chloroplasts using Triton X-100. The oxygen evolution system in these particles was stable; 70of the original activity remained after storage of the particles at 0°C for 7 days. When the particles were treated at pH 9.3, the oxygen evolution was specifically inactivated and three polypeptides having apparent molecular weights of 32,000. 24,000 and 15,000 were simultaneously released. This observation suggests that these polypeptides are associated with the oxygen evolution system of photosynt