472 FATE OF BODY-FOREIGN SUBSTANCES 



KCH(NH 2 ).COOH + H 2 = B.CH(OH).COOH + NH 3 , it 

 being easy in this way to obtain many aminoacids, with dif- 

 ficulty produced hitherto in optically- active form. Thus from 



CH 2 CH 2 



tyrosin, c^ CH.NH 2 , oxyphenyllactic acid Cc^ CH(OH), 



OH COOH OH COOH 



may be obtained; and from phenylalanin and tryptophane 

 their corresponding oxyacids. 50 



Synthetic Formation of Aminoacids in the Animal Body. 

 Our ideas about deaminization processes have been ma- 

 terially extended by Knoop 's discovery of a synthetic form- 

 ation of aminoacids in the animal body. 



Knoop 51 in the first place succeeded, after feeding 



f TT 



phenyl-a-aminobutyric acid, I , in isolat- 



CH 2 .CH 2 .CH(NH 2 ).COOH 

 f 1 TT 



ing phenyl- a-oxybutyric acid, I * , from the 



urine; but after feeding phenyl- a -ketobutyric acid, 



, the acetyl compound of phenyl- a -amino- 



CH 2 .CH,.CO.COOH 



butyric acid. From these observations he proposed the idea 

 that the first phase of oxidation catabolism of aminoacids is 

 a reversible one : 



AMINOACID OXYAMINOACID KETONIC ACID 



R R R 



I/OH NH 8 I +0 R 



6-NH 2 - > CO - > I 



< - I COOH. 



COOH +NH, COOH 



According to this view it would be necessary to assume 

 the formation of a hypothetical oxyaminoacid, arising pos- 

 sibly on the one hand from the aminoacid by the introduction 



80 F. Ehrlich and K. A. Jacobsen (Breslau), Ber. d. deutsch. chem. Ges., 44, 

 888, 1911. 



61 F. Knoop (Freiburg i. B.), Zeitschr. f. physiol. Chem., 67, 489, 1910; 

 F. Knoop and E. Kertess, ibid., 11, 251, 1911. 



