90 



A. I. RINGER 



2. Tjrosin or a-amino para hydroxy phenyl propionic acid. 



COH 



/ \ 

 HC CH 



I II 



HC CH 



\ / 

 C 



CH 2 



CHNH 2 



COOH 



These amino acids are similar to those of the monobasic mono-amino 

 acid group, except that they are derivatives of the phenyl group. 



F. Heterocyclic amino acids. 



1. Prolin or a-pyrolidin carboxylic acid. 

 H 2 C CH 2 



H 2 C CH COOH 



or 



\ 



NH 



Pyrolidin 

 radical 



CH 2 



\ 



CH 2 

 CH 2 

 CH 7 

 COOH 



2. Oxyprolin or hydroxypyrolidin carboxylic acid. 

 HOHC - CH 2 CH 



CH COOH or CHOH 



\ / 

 Nil 



COOH 





