THE PROTEINS AND THEIR METABOLISM 85 



3. a-amino butyric acid. 



It CII '''-";' .': : : - ; SMI^SI": 



CITo 



a-CHNII 2 

 COOH 



4. Valin or a-amino iso-valerianie acid or a-amino p-methyl butyric 

 acid. 



CH,CH, 

 \ / 



a-CHNH, 

 COOH 



5. Lcucin or a-amino y-methyl valerianic acid. 



CH 3 CH 3 



\/ 



Y-CH 



COOH 



'. Iso-leueiii or a-amino (5-metliyl valerianie acid. 

 CH 3 



Y-OH 2 



orr,-p-ci 

 i 



a-CHNH, 

 COOH 



