468 E. MACOVSCHI 



it occurs too fast compared to the rates of the reactions brought about by the 

 enzymes in question under ordinary conditions. In all probability the enzymes, 

 in these cases, affect the coacervates by virtue of being proteins rather than by 

 virtue of being enzymes. What might be called their 'coacervatolytic activity' 

 increases with an increase in their concentration in the solution; in pepsin and 

 trypsin the activity is decreased by denaturation while in papain it is completely 

 destroyed; furthermore, some native proteins which have no proteolytic activity, 

 such as haemoglobin, egg albumin and others [23] behave just like the enzymes 

 referred to in relation to a coacervatc of gelatin and gum arabic. 



Experiments have shown that human gastric juice and duodenal juice give 

 almost the same results as solutions of the corresponding proteohiic enzymes. 

 These experiments showed that the salts of the biliary acids can, to some extent, 

 stabilize the drops of a coacervate of gelatin and gum arabic. However, not all 

 protein-containing coacervates behave like coacervates of gelatin and gum arabic 

 in relation to proteolytic enzymes ; for example, some coacervates obtained from 

 blood serum show quite different properties, so that one can study proteolysis 

 on drops of them. 



It is obvious that the synthesis of proteins, which must have occurred in the 

 remote past at a particular level of development of native coacervates, could 

 have been of decisive significance for the further evolution of coacervate drops. 

 The appearance of proteins with 'coacervatolytic' properties would have led 

 to the rapid destruction of coacervate drops and it was only the synthesis, within 

 the coacervate drops, of proteins which did not destroy these drops which could 

 have had a positive significance for the evolutionary transition from coacervates 

 to the organic formations which constituted the germs of life. 



A few words remain to be said about the introduction into coacervates of 

 artificial and natural formations (structures) containing enzymes. 



The possibility of incorporating, into coacervate drops, solid and liquid 

 particles such as fine particles of Indian ink, indigo, collargol, emulsified droplets, 

 erythrocytes, bacteria, pollen grains, spores and even such unicellular organisms 

 as Euglena, was demonstrated by H. G. Bungenberg de Jong even in his earliest 

 papers [19]. This subject has also been touched on by other authors such as 

 A. S. Troshin [20]. 



Our work in this field has only just begun. By bringing about the formation 

 of coacervates in aqueous suspensions of adsorbent materials on which enzymes 

 are adsorbed; in suspensions of plastids, nuclei and other intracellular forma- 

 tions ; in emulsions of coacervates which have already had enzymes introduced 

 into them and so forth, one may bring about the inclusion of these particles in 

 coacervate drops or the mass of the coacervatc, and one may study the behaviour 

 of the enzymes under these peculiar conditions which approximate to those 

 found in living organisms. 



The ease with which all sorts of suspensions and emulsions can be introduced 

 into coacervate drops is also of interest in connection with the theory of the 

 origin of life. 



It may be supposed that, at the period when coacervates were formed, the 

 waters of the ocean must have been, not merely a solution of various compounds, 



