ENZYMIC DEGRADATION AND BIOSYNTHESIS 69 



to a synthetic growth medium containing the radioactive 

 amino acids. On the other hand, the inhibition of the in- 

 corporation into protein of the "wall" amino acids and 

 leucine, proline, and phenylalanine was as much as 85 to 

 98%. In agreement with the investigations reported by 

 Mandelstam and Rogers,*^ Hancock and Park ** were also 

 able to demonstrate a doubling of the amount of wall (meas- 

 ured by incorporation of [^^C] lysine and glycine) in a simple 

 incubation mixture containing lysine, glycine, alanine, glu- 

 tamic acid, glucose, and uracil but lacking in some of the 

 amino acids essential for protein synthesis. Under these 

 conditions chloramphenicol had no effect on wall synthesis. 

 An examination of the wall formed in the presence of chlo- 

 ramphenicol suggested that it was normal in that the ratios 

 of increase in glutamic acid, glycine, alanine, lysine, and 

 hexosamine (1:5.8:4.2:2.0:1.8) were similar to those pres- 

 ent in the initial wall (1:6.8:2.8:1.9:1.8). 



The synthesis of the cell-wall mucopeptide was markedly 

 inhibited by penicillin and bacitracin, neither of which in- 

 hibited protein synthesis.*^ However, a small amount of 

 mucopeptide is synthesized in the presence of penicillin, 

 and Mandelstam and Rogers *^ found some evidence sug- 

 gesting that it possessed an abnormal composition. Nathen- 

 son and Strominger *^ also studied the inhibitory effect of 

 penicillin on the incorporation of [^^C] lysine and P^P] 

 into wall and cellular protein and nucleic acid of Staphylo- 

 coccus aureus and the incorporation of [^H] diaminopimelic 

 acid and [^^C] glucose into the wall of Escherichia coli. The 

 results presented in Table 22 are again in accord with those 

 of other investigators, showing a marked inhibition of 

 amino acid incorporation into the cell wall but allowing 

 both protein and nucleic acid synthesis to proceed in the 

 presence of penicillin. The inhibition by penicillin of p*C] 

 glucose incorporation into the whole cell wall of Escherichia 



