Some Relationships Between Coacervates and Enzymes 467 



In spite of the apparent similarity with what has been established in the case 

 of emulsions, the mechanism of the effect of coacervate droplets on the reactions 

 in question is completely different. While hydrophobic emulsions of hydro- 

 carbons adsorb and partially inactivate enzymes, coacervate droplets draw the 

 enzymes into themselves from the surrounding aqueous medium, lowering their 

 concentration and, therefore, decreasing their activity. This means that, as 

 D. N. Nasonov [17] would have expressed it, we are here dealing with sorp- 

 tional processes in which an important part is played, not only by the permea- 

 bility of the material of the coacervate, but also by the insertion of 'liquid 

 envelopes' in relation to the enzyme if structures of this sort become differen- 

 tiated on the surface of the coacervate drops, or simply 'liquid surfaces' separating 

 the coacervate drops from the surrounding medium. Naturally, the introduction 

 of lipid complexes into protein coacervates, studied by G. A. Deborin [18] can 

 create new possibilities for changing the properties of the coacervates, causing 

 their properties to be more like those of hydrophobic emulsions. 



The gradual sorption of enzymes by coacervate droplets from the surrounding 

 medium is analogous to the well known sorption of dyes and other substances 

 [19, 20]. We are convinced that study of this process, and also of the possible 

 passing out of enzymes from coacervates, of which A. I. Oparin has reminded 

 us to-day, could give new data for increasing the exactitude of our knowledge of 

 the distribution of enzymes between living material and the vacuoles adjacent 

 to it and other liquids, the interaction between the coacervate surfaces of living 

 material and the enzymic reactions which occur in these same liquids, the intra- 

 cellular and intercellular migration of enzymes, the excretion of enzymes by 

 organisms, by their transmission to the soil through the roots of plants, etc. 



The sorption of enzymes by coacervate drops is also interesting from the 

 point of view of the origin of life. It indicates that the appearance of the first 

 enzymes in coacervate formations could have occurred, not only by their being 

 formed within the coacervates as described by A. I. Oparin [21] (the endogenous 

 method), but also on account of the entrance into the coacervate drops of various 

 enzymically active proteins, if any could have made their appearance in the 

 waters of the Earth independently of the process of coacervation (exogenous 

 method). 



Another field of interest to us is the action of enzymes in the surrounding 

 medium on coacervates as such. With this in view we have, so far, studied the 

 formation and behaviour of a coacervate of gelatin and gtmi arabic in the presence 

 of pepsin, trypsin and papain and some digestive juices [22]. 



It was found that, in the presence of these enzymes, the intensity of coacerva- 

 tion falls so far that, in some cases, e.g. when papain is used, coacervate droplets 

 cannot separate out. The addition of the enzymes mentioned to a ready-made 

 coacervate also has a destructive effect and often leads to the rapid disappearance 

 of the coacervate drops. 



And yet this action of proteolytic enzymes on a coacervate of gelatin and gum 

 arabic is not enzymic in character. It occurs even when the pH of the medium 

 is of such a value that the enzymic activity is inhibited and it is not accompanied 

 by proteolysis in so far as the formation of free amino acids is not observed and 



