Biochemical Processes in the Sinplest Structures 



435 



the invertase of the yeast Saccharomyces globosus which is incapable of fermenting 

 sucrose, is revealed upon treating the cells with ultrasonic waves, or after pro- 

 longed autolysis, these agents disrupting the complex of the enzyme with other 

 high-molecular substances of the cell [12]. 



With these considerations in mind we imdertook to measure the biosynthesis 

 of proteins by determining the increase of protein nitrogen. In similar experi- 

 ments, made with Hver granules Khesin observed [13] a 10-20% increase in 

 protein nitrogen. In our experiments o-i ml of a solution of 19 amino acids, 

 containing 40 mg each amino acid/ml. was added to 2 ml. of the bacterial lysate 

 representing a suspension of protoplasts in buffer solution with the selected 

 concentration of sucrose. The experiments in which we determined the increase 

 of protein nitrogen in the presence of the complete set of amino acids were con- 

 ducted at pH 87, i.e., in conditions ensuring solubility of all amino acids in the 

 reaction mixture. After incubation and precipitation with five volumes of tri- 

 chloroacetic acid (10%) the samples were centrifuged and the precipitates were 

 quantitatively transferred to combustion flasks. 



The data obtained are of a preliminary nature; they show that the maximum 

 increase of protein nitrogen in the protoplasts can be observed when the latter 

 are obtained by lysis in 0-84 M-sucrose solution. In these experiments bacteria 

 lysed in the absence of sucrose and incubated with amino acids in the same 

 conditions served as the control (Table 4). 



Table 4 



Protein nitrogen content of protoplasts after incubation 

 with complete set of amino acids 



These figures show that the increase in protein nitrogen, which to a certain 

 extent proves the biosynthesis of the protein, directly depends on the state of 

 the structure of the protoplasts, to which this process is related in a similar 

 manner as has been found for the incorporation of labelled amino acids. It should 

 be emphasized however that these data are of a preUminary kind, since it is essen- 

 tial to investigate the effects on this process of drugs inhibiting respiration and 

 biosynthesis, for example, dinitrophenol, potassium cyanide, sodium azide and 

 others. Besides, another difficult problem still remains to be solved: the cor- 

 relation which exists between the action of proteolytic enzymes and the con- 



