Biochemical Processes in the Simplest Structures 171 



In such experiments it must, for one, be kept in mind that coacervates formed 

 from certain components can exist only within relatively narrow Umits of pH, 

 while the activity of the enzyme to be included into the system requires, in its 

 turn, a definite optimal range of actual acidity. Therefore the success of the work 

 can be assured only if the coacervate selected for observing enzymic activity 

 can exist in the pH range optimal for the activity of the enzyme in point. 



Let us consider some actual experimental examples of the inclusion of enzymes 

 into coacervate drops. The condition common to all these experiments is that 

 the coacervates should be prepared from diluted solutions (o-oi-o-i%), at a 

 definite temperature. Thirty minutes after incorporation of the enzyme and 

 substrate into the coacervate droplets, the latter are separated from the solution 

 by centrifugation (1500-3000 rev./min), and in the sediment and supernatant 

 thus obtained determinations are made of the products of action of the enzyme 

 embodied in the coacervate drops. 



To study the effect of a-amylase [i] a coacervate was obtained which consisted 

 of soluble starch, gelatin and of protamine sulphate prepared according to 

 Kossel's [2] method from the spawn of Amur salmon. Coacervation was effected 

 in the following way: 0-4 ml of a 0-5% solution of protamine sulphate, i-2 ml 

 of 0-67% gelatin solution and o-i ml a-amylase solution, containing 0-2 mg 

 enzyme, were added to 0-4 ml. of o-i% soluble starch. The mixture was brought 

 to pH yo with the temperature at 50°. At fixed intervals samples were taken, 

 stained with iodine and photographed with an ultraviolet microscope and 

 chromoscope on colour film. 



Figure la shows coacervates containing starch; Fig. lb coacervates in which 

 the starch was broken down to amylodextrins ; Fig. ic to erythrodextrins ; and 

 in Fig. id it is seen that the degradation of starch reached a stage approaching 

 achroodextrin. 



Further analysis showed that under the given conditions the activity of the 

 enzyme in the coacervate was lower than in the aqueous solution of the con- 

 stituents from which the coacervate was obtained. Evidently, in the coacervate 

 drops possessing considerable viscosity due to their high content of protamine 

 and gelatin, the rate of movement of the substances diminishes, while the ad- 

 sorption capacity of the drops is increased. The experiment shows how marked 

 an influence even a structure so primitive in the biological sense as are coacer- 

 vate drops may have on the course of individual enzymic reactions. 



A study of the degradation of starch to sugar in coacervate drops was made 

 with the use of /3-amylase [3]. To obtain coacervate drops, 2 ml of 0-67% 

 aqueous solutions of gelatin and gum arable, taken in the ratio 5 : 3, were mixed 

 with 0-5 ml of a 1% solution of phosphorylated or soluble starch and 0-5 ml 

 of 0-05% amylase solution. The mixture was brought to pH 4-82-4-85 with the 

 temperature at 40-42° and kept 15 minutes at this temperature. Preliminary 

 sampHng showed that the amount of starch of the coacervate drops was equal 

 to 13-1% of the total starch present in the whole coacervate (drops and liquid 

 phase). 



Calculation for unit volume shows that the concentration of starch in the 

 coacervate drops was 4-5 times higher than in the equilibrium fluid. The ^- 



