Submitted November 4, 1996; revision submitted January 23, 1997.
Photosynthetic oxygen is currently believed to be derived from water. A number of H2O analogs interact with the water-oxidizing complex. Of special interest among them is hydrogen peroxide in view of its possible involvement in photosynthetic O2 production. Presumably, H2O2 represents an intermediate product of H2O oxidation and plausibly even the primary electron donor. In some cyanobacteria and algae, O2 evolution is abolished under anaerobic conditions. Investigation of the role of H2O2 in photosynthetic O2 evolution is a promising field of research.
KEY WORDS: photosynthesis, photosystem II, electron transfer, O2 evolution, role of H2O2.