Short-Term Carbon Dioxide Fixation in Mouse Liver

IN a previous report 1 , there were presented findings which were unexpected if the entire polycarboxylic acid cycle were involved in carbon dioxide fixation by animals. At 5 and 15 min. after the injection of radioactive sodium bicarbonate (NaH 14 CO 3 ) (obtained as Ba 14 CO 3 from the Atomic Energy Commission, Oak Ridge, Tennessee) there appeared to be a more direct path of carbon to succinate than that previously postulated. In addition, the labelling in such acids as α-ketoglutarate, citrate and aconitate was not measurable. It was thought desirable to examine the path of carbon dioxide employing paper chromatography, because by this technique compounds retained by the silica gel (used in previous studies) which escaped examination would become detectable.