THE METABOLISM OF PROTEIN 605 



(2) The amino dibasic acids: 



Aspartic, which is aminosuccinic acid, 



CH 2 COOH 



I 



CHNH 2 COOH; and 



Glutaminic, which is aminoglutaric acid, 

 CH 2 



CH 2 - COOH 

 CHNH 2 COOH. 

 Lastly there are the diamino acids, in which two groups exist : 



Lysine a e-diaminocaproic- acid, 



NH 2 



NH 2 CH 2 - CH 2 - CH 2 - CH 2 - CH 2 - CH 



COOH. 



Arginine o-amino 8-guanidine-valerianic acid, 



NH 2 



HN C NH 2 



NH.CH 2 - CH 2 - CH 2 - CH 



COOH 



The guanidine group in this acid is of interest because of its close relationship to 



NH 2 r l ~ 



/ 

 urea, which is O = C 



"NH, 



