AMMONIUM SALTS IN PROTEIN SYNTHESIS 69 



of the retained nitrogen taking place. 57 It would, however, 

 be decidedly misleading to regard this as evidence indicating 

 protein synthesis from ammonia and nitrogen-free material. 



The above findings have been confirmed by independent 

 observations of Abderhalden to the extent that after addi- 

 tion of ammonium acetate to a nitrogen-free diet consisting 

 of rich fatty and carbohydrate constituents there may ensue 

 a nitrogen retention. 58 



In connection with the observations (to be discussed later 

 in detail) of Knoop, Embden and their associates upon the 

 transformation of a -ketonic acids into aminoacids by the fol- 

 lowing schema : 



R (_/Il2 iv OJtli 



I I 



CO+NH, ^_ CH NH.+O 



I I 



COOH COOH, 



it is not difficult to think of a shifting of the equation between 

 aminoacids and ketonie acids by the introduction of am- 

 monia in a way to bring about synthesis of aminoacids, the 

 ketonic acids, however, to be derived from nitrogen-free 

 food constituents. 



In further studies 59 Abderhalden, however, pointed out 

 that it is a matter of great difficulty to draw any consistent 

 conclusion from the results. In reality it turned out that 

 even without nitrogen administration he was able by full 

 diet of carbohydrates and fats to maintain for a long time 

 constant body weight and, in fact, for short periods to 

 induce increase of weight of the experiment animals; so 

 that apparently it is inadmissable to come to any conclusions 

 as to protein synthesis after administration of ammonium 

 salts whether there be weight loss or weight increment. 



57 E. Grafe, Kongr. f. innere Med., Wiesbaden, 1912; E. Grafe and V. 

 Schlapfer, Zeitsch. f. physiol. Chem., 77, 1, 1912; E. Grafe, ibid., 78, 485, 1912; 

 cf. claim for priority by W. Voltz, ibid., 75, 415, 1912. 



M E. Abderhalden, ibid., 78, 1, 1912. 



K E. Abderhalden and P. Hirsch, Zeitschr. f. physiol. Chem., 80, 136, 1912. 



