Aspartic Acid. 



Dibasic acid, 

 reaction acid 



Branched Polyp eptid. 

 Glycyl-alanyl-diaspartic-Acid 



This tetrapeptidcan develop linkages along 

 two tranches, beside the main chain. Its 

 reaction is acid due to the preponderance 

 of carboxyl groups. Such polypeptids 

 linked would give an acid protein. 



Serin 



Prolin 



Valin 



Arginin 



Diamino acid, 

 reaction basic 



Schematic representation of a protein molecule 

 PLATE II. SCHEMATIC REPRESENTATION OF A PROTEIN MOLECULE. 



This is the supposed composition of the protamin of the salmon (salmine). Six 

 tripeptids, each composed of two molecules of the diamino acid arginin and one 

 monoamino acid, are linked together. The protein is strongly basic because of the 

 preponderance of the amino groups. 



