Tvfonoamino acids 

 reaction neutral 



Dlpeptidi 



Glycccdll 



Glycyl - g lyciri 



Alar.in Alanyl-alanin 



Two possible dioeotids between glycocoll and alanin 



Glycyl-alanin 



Alanyl-glycin 



Six possible tripeptida 

 between glycocoll, alanin. 

 and leucin 



Leucyl- alanyl- glycin 



Alanyl- glycyl-leuctn 



L e ucyl- gly'cy 1- alanin 



Tryptoph 



Histidin 



Cystein 



Straight chain polypeptid (heptapeptid) 

 Glycyl-alanyl-leucyl^tyrosyl-tryptophyl-histidyl-cystein 



PLATE I. SCHEMATIC REPRESENTATION OF THE AMINO ACIDS. 



The neutral amino acids each contain a basic aniino group (blue) and an acid 

 carboxyl group (red), which neutralixe eacli other. These amino acids can link 

 themselves to one another in straight chains, in any combination and permutation, 

 the amino group uniting with the carboxyl group. 



