THE PIGMENT-PROTEIN COMPOUND IN PHOTOSYNTHETIC BACTERIA : I. THE EXTRACTION AND PROPERTIES OF PHOTOSYNTHIN.
1. Photosynthetic bacteria in water suspension break open when treated with supersonic vibration thus liberating the cell contents, including a water soluble protein to which is attached the otherwise water insoluble pigments, bacteriochlorophyll and carotinoids. Both types of pigments appear to be combined with the same protein. 2. The protein pigment compound is insoluble in the region of pH 3.0 to 4.5 and in neutral solution can be completely precipitated by 0.5 saturated (NH(4))(2)SO(4). It is soluble in distilled water and adsorbable on fullers' earth. 3. Supersonic extracts of photosynthetic bacteria do not have the ability to carry on photosynthesis, but will act as a photocatalyst for the oxidation of ascorbic acid with visible or infrared radiation. The rate of the photochemical oxidation is proportional to the light intensity.
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Department of Biochemistry, Harvard Medical School, Boston, and the Cruft Laboratory, Harvard University, Cambridge.