ENZYME SYSTEMS IN PHOTOSYNTHESIS.

The distinction between photosynthetic and nonphotosynthetic cells lies in the manner in which ATP and PNH2, needed for carbon assimilation, are formed. Photosynthetic cells form these compounds at the expense of radiant energy whereas nonphotosynthetic cells form them at the expense of energy released by dark chemical reactions. Thus, the key problem of photosynthesis is how the photosynthetiiic apparatus converts the suns radiant energy into the chemical energy of ATP and PNH2. This is the area with which this project has been concerned. Work was begun on the premise that in photosynthesis, as was the case earlier in fermentation and respiration, the elucidation of the partial reactions and mechanisms of energy conversion would most likely come when the process was reconstructed outside the intact cell. The work, therefore, was concentrated on developing effective biochemical techniques for carrying out photosynthesis outside theehe cell.