176 A. I. OPARIN 



the Lowry-Lopez method. lOO /xg of orthophosphate per 150 mg of bacterial 

 mixture were added to the reaction mixture. The total volume of the samples 

 was I ml (Table 3). 



The figures in the table show that mineral phosphorus from the experimental 

 mixture is assimilated both by the intact cells and by the protoplasts obtained 

 after lysis at different sucrose concentrations. According to the data given by 

 Kane & Umbreit [8], and recently by Rose & Ochoa [9] the disappearing phos- 

 phate is recovered in the fraction of easily hydrolysed organic phosphorus com- 

 pounds. According to our data the phosphorus of the mentioned fraction not 

 only does not increase but even decreases, which may indicate an accimiulation 

 of organic phosphorus compounds of the type of polynucleotides. Such observa- 

 tions were made earHer by A. N. Bclozerskii for actinomycetes [10]. 



It should be noted that the nature of the process and its intensity are practi- 

 cally imaltered in protoplasts obtained at different concentrations of sucrose, as 

 opposed to the processes of respiration and of incorporation of labelled amino 

 acids. The process is, evidently, already impaired in the protoplasts from 0-84 m- 

 sucrose solution, as compared with the intact cells; thus it is very sensitive and 

 readily subject to 'uncoupling'. 



The findings concerning the transformation of the fractions of phosphates in 

 different preparations of protoplasts confirm our assumption that the incorpora- 

 tion of labelled amino acids requires but very small amounts of energy, as pro- 

 duced even in such disrupted systems as the protoplasts obtained under condi- 

 tions of lysis in the presence of 0-44 M-sucrose. Obviously it is not the lack of 

 energy which is the cause of suppression of the process of incorporation in 

 protoplasts prepared under conditions of lysis at sucrose concentrations lower 

 than 0-44 M. Here we are deaUng with some kind of serious damage to the cell 

 structure which completely inhibits the incorporation of labelled amino acid 

 into the protoplasts. 



Preliminary experiments were further carried out on the biosynthesis of pro- 

 tein in protoplasts prepared as described. To perform such experiments was of 

 interest both with a view to investigating the process of protein biosyntheses 

 as such, and for the purpose of elucidating the role of cell structure in this process. 

 A number of studies, particularly those pubHshed recently, have been devoted 

 to investigation of the process of protein biosynthesis in bacterial extracts, or 

 cellular fragments. As an example of this we can cite the well-known experi- 

 ments of Gale with fragments of the cell of Staphylococcus aureus and the work 

 of the French scientists Nisman, Hirsch, Marmur & Cousin [11]. In most of 

 the studies on protein biosynthesis in different objects the process was measured 

 by the increase in activity of some enzyme, selected by the investigator. Yet we 

 believe that the increase in enzymic activity which takes place during incubation 

 of cells, disrupted by one method or another, with amino acids and some other 

 substances (particularly ATP) cannot in itself be considered as an entirely reHable 

 indication of the synthesis of protein. 



The fact is that the enzymes, as shown by the author's earUer studies as well 

 as those recently performed in his laboratory, can exist in the cell in a bound, 

 inactive state, and can be liberated by the action of various factors. For example. 



