APPLIED RESEARCH CONCERNING ARTIFICIAL PHOTO-SYNTHESIS

The structure, biochemistry, and photosynthetic function of the spinach chloroplast was investigated to gain sufficient knowledge to permit a similar active system to be synthesized by man. Chloroplasts were isolated and fragmented. Relatively narrow-range size groupings of the fragments were obtained by differential centrifugation. These fractions were assayed physiologically and chemically. Maximal functional activity, in terms of electrons transferred or oxygen evolved under illumination, was found in particles sedimenting between 20,000 g and 50,000 g. Various anion concentrations were tested. An attempt to obtain photoactivity from a dried chloroplast layer -- a first approximation of an artificial system -- was only partially successful. The studies indicate that activity in the fractions varies, probably reflecting altered structural or chemical composition. Results are discussed in relation to proposed models for the fine structure of the chloroplast and the basic photosynthetic unit.