640 



METABOLISM 



CH 



NH 

 CH = C.CH 2 . CH. NH 2 -COOH. 



The last two are also called heterocyclic compounds, of which there 

 is another, viz.; 



Proline (and oxyproline), which is a-pyrrolidine carboxylic acid: 



CH 2 CH 2 



CH 2 



CH.COOH 



\ 



NH 



Other amino acids are: 



(2) The amino dibasic acids: 



Aspartic, which is aminosuccinic acid, 



CH 2 COOH 



I 

 CHNH 2 COOH; and 



Glutaminic, which is aminoglutaric acid, 

 CH, 



CH 2 -COOH 



CHNH 2 COOH. 



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



Lysine a e-diaminocaproic acid. 



NII 2 



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



\ 



COOH. 



Arginine a-amino 5-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 



/ 



urea, which is O = C 



