PURINE AND PYRIMIDINE ANALOGUES 293 



synthesized via uridine diphospho-N-acetylglucosamine and a uridine 

 diphospho-mucopeptide similar to that isolated by Park [ii]. Equally it 

 seemed possible that glycine which did not accumulate in any form associa- 

 ted with 5-fluorouridine might be incorporated into the wall mucopeptide 

 via a co-enzyme other than uridine. If such a precursor also contained 

 other amino acids besides glycine, the differences in molecular proportion 

 between our cell wall mucopeptides and those of other strains [13] might 

 be explained. Earlier work, already described, showed that some analogues 

 of thymine, guanine, and adenine did not inhibit mucopeptide synthesis or 

 lead to the accvmiulation of compounds containing bound N-acetylhexosa- 

 mine which were soluble in trichloroacetic acid. 



TABLE II 



The Effect of Substituted Benzimidazoles on the Incorporation of [i-"C]- 

 Glycine and [G-^*C] Lysine into Material Insoluble in Hot Trichloroacetic 



Acid 



The organisms were incubated under conditions [8, 10] for cell wall synthesis 

 such that little or no protein synthesis took place. 



Another group of analogues, the substituted benzimidazoles, have been 

 shown to inhibit [8-^^C]-adenosine incorporation into ribonucleic acid 

 of chorioallantoic membrane [21, 22] and to inhibit incorporation of 

 amino acids into trichloroacetic acid insoluble material from staphy- 

 lococci [23, 24, 25]. The effect of these substances upon cell wall 

 formation under our conditions was examined. On the hypothesis that 

 the small amount of material referred to above as having been isolated 

 from cells treated with o-i /^mole/ml. of fluorouracil, which contained 

 glutamic acid, glycine, and alanine but not lysine, might be a cell-wall 

 precursor, the effects of the substituted benzimidazoles on the incorpora- 

 tion of glycine and lysine were compared. It was found (see Table II) that 

 two of the compounds inhibited incorporation of both amino acids when 

 tested in the same system as used before, but that both amino acids were 



