The Energy of Urea Synthesis

This study of the energy changes accompanying the synthesis of urea by living tissue from ammonia and carbon dioxide was undertaken in order to obtain more information regarding the causes of the specific dynamic action of protein; and because this reaction seems to be particularly suitable for the study of the energy changes in biological coupled reactions. In the synthesis of urea from ammonia and carbon dioxide (in which a large fraction of the ammonia is converted) there is a gain in free energy, which can be derived only from some other free energy liberating reaction.