Photochemical carbon dioxide fixation by cell-free leaf macerates

Cell-free leaf macerates which exhibit an increase in carbon dioxide fixation upon illumination have been prepared. Over 70% of the increment of fixation due to light is in phosphoglyceric and pyruvic acids. Addition of glyoxal or 2-phosphoglycolaldehyde increases the amount of light fixation without increasing the dark fixation. These results demonstrate the presence in cell-free leaf macerates, prepared as described in this article, of an enzyme system capable of fixing carbon dioxide in phosphoglyceric and pyruvic acids and of utilizing radiant energy absorbed by chlorophyll for this fixation and suggest that glyoxal may be closely related to the 2-carbon acceptor for carbon dioxide which functions in photosynthesis.