ALBUMINS OR PROTEINS, 

 etc. Albumin etc. 



189 



Polypeptides of high molecular weight which for the most part still 

 contain all the amino acids 



/\ /\ /\ 



Amino Poly- Amino Poly- Amino Poly- 

 acid peptides acids peptides acids peptides 



Amino acids 



Decapeptides 



Amino acids 



Amino acids 



Decapeptides 



Amino acids 



Pentapeptide 



| ^ Amino 

 Tetrapeptide v acid 



Peptone 



\ 



Amino 



Tripeptidev acid 

 I Amino 



Pentapeptide 



/\ 

 Tripeptide Dipeptide 



/\ /\ 



Amino Dipeptide Amino Amino acid 

 acid /\ acid 



Amino acid Amino acid 



Dipeptide^ acid 



i Amino 

 acid 



This is, of course, only a scheme, and we are frank in stating that 

 future investigations alone can establish its validity. Many other com- 

 binations are possible. We can easily imagine that the amino acid chains 

 also break down in such a manner that the amino acids are not produced 

 immediately, but that chains are formed, containing only a part of the 

 original amino acids occurring in the polypeptide. In this connection we 

 are reminded of dialanylaspartic acid. If we assume that the chain is 

 lengthened from the alanine group, one of the chains could very easily be 

 split off, leaving an " aspartic-acid-mono-polypeptide." We must also 

 remember that there are polypeptides which are evidently not affected by 

 the digestive ferments. We can very easily imagine such combination as 

 a result of our investigations concerning the behavior of the synthetical 

 polypeptides to the pancreatic ferments. It is not without interest, that 

 the mixture of polypeptides observed in the tryptic digestion of albumin 

 contained large amounts of phenylalanine and proline, the very acids from 

 which synthetic peptides were formed that resisted the action of ferments. 



If, departing from the plan of our lectures, we attempt here to unravel 

 a problem which, according to the experimental knowledge at hand, is not 

 yet fully ripe for discussion, this is done partly because many discoveries 

 give important support to these views, and largely because only upon such 

 a foundation are we able to obtain a clearer understanding of the breaking 



