DYNAMIC ASPECTS — AMINO ACID POOL TURNOVER 633 
METABOLIC POOLS AND THE BIOSYNTHESIS OF PROTEIN 
DEAN B. COWIE 
Carnegie Institution of Washington, Department of Terrestrial Magnetism, 
Washington, D.C. (U.S.A.) 
The study of the endogenous flow of carbon in microorganisms has been extremely 
valuable in elucidating many of the essential steps in the biosynthesis of protein. 
Since this carbon flow is dependent upon many environmental factors, often affecting 
cellular biochemistry and final organic composition, it is important to ascertain what 
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Fig. 1. Steady-state distribution of carbon and phosphorus among chemical fractions of the cell. 
processes are directly involved in protein synthesis and to describe how these processes 
are influenced by environmental alterations. 
Microorganisms, capable of exponential growth in a well-defined synthetic me- 
dium, provide a most valuable system for the investigation of such problems. With 
such a system a “standard” carbon flow may be defined and essential metabolic 
steps recognized. As an example of such a system the discussion here will center 
References p. 645 
