294 H. J. ROGERS AND H. R. PERKINS 



equally affected. The third, 5, 6-dimethylbenzimidazole, was only weakly 

 inhibitory but rather more active in inhibiting lysine incorporation than 

 that of glycine. No definite accumulation of glycine-containing compounds 

 was found. Full analysis of the mechanism of the inhibition has not yet 

 been attempted but it does not seem to be possible to inhibit differentially 

 the two possible pathways of synthesis in an obvious manner by means of 

 the substituted benzimidazoles. It may be, of course, that even if two such 

 pathways exist, it is impossible to obtain a polymer principally made from 

 only one set of precursors. If this were so, then one would not expect to 

 be able to inhibit the incorporation of amino acids differentially, although 

 earlier work with penicillin [8] held out promise of such possibilities. 



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