2l6 ABIOGENIC O RG AN I C- C H E MI C AL EVOLUTION 



led to the formation of polypeptides containing serine and 

 threonine. 



The reaction of aldehydes with polyglycine adsorbed on 

 the surface of solid bodies gives rise to the conditions needed 

 for asymmetric synthesis. It is clear that if polyglycine was 

 adsorbed in its cis forms, so that the side-chains could only 

 react on the outside, the amino acid residues being synthesised 

 would all have the same spatial configuration, at least within 

 each particular polypeptide chain 



H H R H R 



Grl2 ClHo CHo C G C* 



^ ^C — NH''^^ ^C — NH'^^ ^ > ^ ^C — NH C NH 



II II II II 



GO O O 



This hypothesis was confirmed by experiments by Akabori 

 and Ikenaka on the asymmetric synthesis of phenylalanine. 



According to Akabori there might thus have been formed 

 in the primaeval hydrosphere complicated polymers of amino 

 acid of high molecular weight, rather similar to proteins in 

 their polypeptide structure. This synthesis of protein-like 

 substances followed a completely different path from that 

 which it now follows in living organisms. 



It is characteristic of living organisms that in them the 

 synthesis of proteins, like that of nucleic acids, is based on 

 a process which has already been elaborated during the slow 

 evolution of the organism. They arise as the product of 

 this organisation and their specific biologically important 

 peculiarities and properties are the result of this mode of 

 origin. 



As we have seen in this chapter, the comparatively simple 

 laws of thermodynamics and chemical kinetics were essen- 

 tially what determined the course of chemical events in the 

 waters of the primaeval ocean. These principles provide 

 an understandable mechanism for the formation of sugars, 

 amino acids, purine and pyrimidine bases and even their 

 more or less complicated polymers. 



Many contemporary authors believe that, on the basis of 

 these same laws, we shall also be able to give an explanation 



