Oxygen Evolution of Lyophilized Photosystem II Membranes
Lyophilized photosystem (PS) II membranes showed 70% of the activity of oxygen evolution of the control PS II membranes. The yield of the flash-induced oxygen evolution of the lyophilized PS II membranes peaked at the sixth flash in aqueous medium, indicating that the water-oxidizing enzyme was apparently reduced to “S−2 state” by lyophilization. When the lyophilized PS II membranes were adapted in the dark after preillumination in aqueous medium, the oxygen evolution oscillated as the control showing the maximum at the third flash. On the other hand, when preilluminated under dry conditions, the oxygen evolution was maximal at the sixth flash. These results indicate that the water bound to the water-oxidizing enzyme is depleted by lyophilization, and two photons and the strongly bound water are required for recovering the S0 from S−2 states.
KeywordsOxygen Evolution Photosynthetic Oxygen Evolution White Continuous Light Quadrupole Mass Analyzer Flash Number
Unable to display preview. Download preview PDF.
- 6.Kuwabara, T. and Murata, N. (1982) Plant Cell Physiol. 23, 533–539Google Scholar