264 ORIGIN OF STRUCTURES AND FUNCTIONS 



of enzymes in which, as will be shown later, the more com- 

 plete the organisation of any particular system the higher its 

 energetic efficiency and the greater the extent to which the 

 energy produced by it can be used for the carrying out of 

 vital processes, in particular for the formation of the proteins 

 of protoplasm. In the course of these metabolic processes 

 there arise many kinds of high-energy compounds and the 

 energy which they yield can be used, in one way or another, 

 for biological syntheses. The best known of these compounds 

 is adenosine triphosphoric acid (ATP), which can hand over 

 the energy of its phosphate linkages by the transphosphoryla- 

 tion of a number of organic compounds. 



F. Lipmann''* and other authors (e.g.'") have suggested 

 that the increment of energy required for synthesis of peptide 

 bonds when amino acids combine may be obtained by the 

 phosphorylation of their amino or carboxyl groups at the 

 expense of ATP or some analogous substance. This sugges- 

 tion is confirmed by various sorts of model experiments in 

 which hippuric acid is synthesised from glycine and benzoic 

 acid,'^^ and also by the synthesis of the tripeptide, gluta- 

 thione, from its component amino acids in slices and 

 homogenates of various organs'" as well as in experiments 

 with yeast. '^* S. Yanari and his colleagues'-^ have shown 

 recently that an enzyme which they isolated from pigeon's 

 liver can bring about the synthesis of glutathione from its 

 amino acids only when the system contains ATP and glyco- 

 lytic processes are proceeding. 



Lipmann's hypothesis concerning the biosynthesis of pro- 

 teins is, to some extent, confirmed by the fact that anything 

 which interferes with phosphorus metabolism hinders this 

 synthesis. Thus, in the experiments of E. F. Gale and J. P. 

 Folkes,'^° fragments of staphylococcal cells were able to in- 

 corporate isotopically-labelled amino acids and synthesise 

 proteins from complete collections of amino acids only on 

 the addition of ATP and hexose diphosphate as sources of 

 energy. Analogous phenomena were observed by F. B. 

 Straub'^' during the synthesis of amylase by homogenates 

 of the pancreas. 



On the other hand, it must be pointed out that nobody 

 has yet succeeded in directly observing the phosphoryla- 



