Carbon Dioxide Fixation in the Ja-1 Sarcoma in Vitro.

Carbox dioxide fixation studies were conducted with rapidly growing JA-1 sarcoma cells in vitro. Isotope was isolated in asparagine, aspartic acid, glutamic acid, and glutamine. Chemical degradation of these compounds suggested three sites of fixation. They were carbon dioxide condensation with (a) pyruvic acid, (6) propionyl CoA, and (c) a three-carbon fragment such as the isopropyl carbons of leucine. The first reaction was found to be only slightly reversible.