PART V 

 PROTEINS AND AMINO-ACIDS 



A METHOD FOR THE EVALUATION OF THE 

 RATE OF PROTEIN SYNTHESIS IN MAN 



D. RITTENBERG 



Until now the problems to which this conference has 

 devoted its attention have in the main been of such character 

 that, complex though they were, they could be clearly formu- 

 lated. Such unfortunately is not the case for the question 

 concerning which I am expected to enlighten you. The syn- 

 thesis of proteins is one of the characteristic functions of the 

 living cell. Unfortunately we do not clearly understand the 

 nature of a protein and would surely have difficulty in agree- 

 ing on definitions of the words protein or synthesis and almost 

 certainly on the meaning of the phrase "protein synthesis." 

 Rather than attempt to formulate definitions which exactly 

 define these terms I shall depend on one patterned after that 

 used by Eddington (1949) to define physical knowledge. 

 Protein synthesis will consist of that which any right thinking 

 person would accept as protein synthesis. The difficulty in 

 defining the subject matter of this lecture arises from 

 ignorance. Any more exactly formulated de finition would 

 almost surely arise to plague me in the future . 



Recognizing that I am assuming that we int uitively under- 

 stand the meaning of the phrase "protein synthesis," let us 

 consider some kinetic aspects of this problem. We now know, 

 as a result of recent studies, that the tiss ue proteins are 

 rapidly being formed and degraded. Indee d, the proteins 



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