180 E. F. Gale 



is markedly more sensitive to chloramphenicol than any 

 incorporation reaction and, moreover, inhibition of protein 

 synthesis proceeds to completion. 



Table II shows that penicillin and bacitracin inhibit the 

 incorporation of certain amino acids and that the inhibition 

 resembles that by chloramphenicol in reaching a different 



Table II 



Inhibition of Amino Acid Incorporation (Condition 1) by 



Antibiotics 



% Inhibition by 



plateau level in each case but differs in that not all incorpora- 

 tion reactions are affected. The inhibitions by the three anti- 

 biotics are significantly the same whether incorporation is 

 promoted by RNA or DNA, consequently the plateau effects 

 are not due to differentiation between the nucleic acids. 

 Chelating agents. Attention has been paid to the possibility 

 that metal activation is involved in the promotion of incorpor- 

 ation by nucleic acids. A preliminary survey of the action of 

 chelating agents indicated that glycine incorporation was 

 highly sensitive to inhibition by 8-hydroxyquinoline. No 

 significant inhibition was obtained with 0-01 M-versene or 

 a:a-dipyridyl. 



8-Hydroxyquinoline. The inhibition by 8-hydroxyquinoline 

 (oxine) is unusual in that 10 ~^ M-oxine produces 80-90 per 



