Experimental Demonstration of the 



Occurrence of Metabolic Processes in 



Simple Proteins 



M. G. KRITSMAN & A. S. KONIKOVA 



Institute of Therapeutics, Academy of Medical Sciences of the U.S.S.R., Moscow 

 Institute of Surgery, Academy of Medical Sciences of the U.S.S.R., Moscow 



One of the important questions at this stage in the study of the problem of the 

 origin of hfe is the question of what were the actual evolutionary forms of the 

 earhest period of the existence of living matter, i.e. at what level of complexity 

 did chemical processes become biological. 



From evidence available to science it is an incontestable fact that this 

 transition could not have occurred before the appearance of a complicated 

 chemical substance such as a protein. Until now, however, there has been acri- 

 monious discussion as to whether the appearance of proteins was enough for 

 the transition from chemistry to biology to take place or whether an even greater 

 complexity of material was necessary for this purpose. 



In our attempts to find out the truth about this question, the answer to which 

 would lead directly to the discovery of the actual way in which life arose and 

 developed, a leading part is played by the study of processes of formation and 

 decomposition, i.e. the metabolism of proteins in biological systems of varying 

 degrees of complexity, because it is by means of such processes that such systems 

 can reproduce themselves and forms of life develop. 



The application of the method of isotopic tracers has opened up great possi- 

 bilities in this field of study. 



The transfer of labelled, free, structural entities from the medium into 

 protein molecules has been widely used as a generally acceptable indication of 

 the formation of proteins. By using this method it has been estabUshed that 

 there are differences in the rate and means of formation of proteins in the intact 

 organism, in hving sections of various tissues, in isolated cells and their com- 

 ponent parts and even in homogenates and lysates of cells. 



It has thus been found that the process of formation of proteins is essentially 

 similar in isolated biological systems and in the intact organism. 



The important fact revealed by these investigations was that the ability to 

 synthesize proteins was retained when the cellular and intracellular structure 

 was disrupted in various ways which led to different degrees of disintegration 

 and different degrees of complexity of structure of the fragments, which may 

 even have neither a definite biological nor a definite chemical nature. 



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