312 



THE DUCTLESS GLANDS 



I H 



V 

 c 



s 



C = C *CH 2 CH 2 COOH 



C O H 



C N 



i 



I H 



\/ 



C 



(2) Enol form 



C C = C CH 2 CH 2 COOH 



COOH 

 NH 2 



(3) Open -ring form 



H 



H C C C CH 2 CHNH, 



I II II I 



COOH 



H C C C H 



C 



J. A 



Tryptophane 



. 



\ 

 I/ 



C C = C CH 2 CH 2 COOH 



C OH 



I 

 H 



C N 



/\ 



O H 



H 



(4) Amino-lo'drate form 



