giO ORGANISATION IN SPACE AND TIME 



from mixtures of egg albumin with its isoelectric point at 

 about pH. 5 and clupeine with its isoelectric point at i2-i. 

 It has also been possible to incorporate enzymic proteins in 

 coacervates while retaining their catalytic properties. ^^ 



Fairly detailed studies have also been made of coacervates 

 containing nucleic acids, for example a coacervate containing 

 three components, gelatin, gum arabic and the sodium salt 

 of a yeast nucleic acid.^^ By means of studies using ultra- 

 violet light it has been possible to determine the absolute 

 amount of nucleic acid in a single drop of coacervate.^" It is 

 often found that a coacervate drop composed mainly of 

 gelatin and gum arabic has droplets within itself composed 

 of gelatin and nucleic acid (Fig. 27). 



It is easy to form coacervates by the interaction of proteins 

 Avith phosphatides, sterols, glycerides and other lipids. In 

 particular, serious study has been given to protein-lipid 

 coacervates" composed of lecithin and various proteins 

 including casein, egg albumin, glycinin, clupeine, gelatin, 

 etc. Gelatin can also form coacervates with other lipids. 

 Bungenberg de Jong has recently paid special attention 

 to the coacervate formed from gelatin and potassium oleate, 

 because this coacervate has a very interesting structural 

 formation and fine bimolecidar boundary membranes. ^^ 

 Potassium and sodium oleates can also form coacervates with 

 such proteins as egg albumin, serum albumin, various globu- 

 lins, etc. Dervichian also obtained protein-lipid coacervates 

 from haemoglobin and the albumin and pseudoglobulin of 

 blood with myristoylcholine. 



Basing his opinion mainly on his own work ^vith gelatin, 

 Dervichian naturally arrived at the conclusion that the 

 phenomenon of coacervation is not, in itself, associated with 

 any chemical combination between the substances taking 

 part. But it certainly does not follo^v that combinations of 

 this kind cannot, in general, occur in coacervates. Thus, in 

 my own laboratory, stable compounds of protein and gum 

 arabic have been found to be present in the corresponding 

 coacervates.''^ G. A. Deborin and his colleagues^* obtained 

 compounds of egg albumin Avith ergosterol having properties 

 similar to those of natural lipoproteins. Doubtless nucleic 



