78 F. §ORM [5 



approach to this problem involves the separation from partial hydrolysates 

 and the further study of such peptides as differ markedly in some manner 

 from the other peptides in the hydrolysate, and which may by virtue of these 

 differences be isolated as a separate group. A very interesting contribution 

 of this kind is the work of Tuppy who, by a comparison of the coloured 

 peptides obtained by the partial hydrolysis of cytochrome-c, established the 

 identity of the amino acid sequence in the neighbourhood of the point of 

 attachment of the pigment in a number of animal species.^ 



In our laboratory we have for some time past been carrying out com- 

 parative studies on the microstructure of certain proteins,^ in particular of 

 chymotrypsinogen and trypsinogen, and of the haemoglobins and myoglobins 

 of various animal species. In this work we concentrate on the isolation and 

 comparison of lower peptides containing amino acids which constitute only 

 a relatively small fraction of the total residue number of the proteins studied 

 and which, moreover, are easily separated from the other peptides. These 

 conditions are met particularly in the case of peptides containing cysteic 

 acid (derived from cystine and cysteine by oxidation), arginine, lysine, or 



Table 1 

 FRACTIONATION SCHEME FOR PEPTIDE MIXTURES 



Partial hydrolysate 



five-compartment electrophoresis 



basic peptides 



multi- Dowex 50 



compartment 

 electrophoresis 



(descending 



paper 



electrophoresis) 



paper paper 



chromatography chromatography 



neutral peptides 



oxidation, 



five-compartment 



electrophoresis 



acidic peptides 



cysteic acid 

 peptides 



neutral 

 peptides 



paper paper 



chromatography chromatography 



individual 

 peptides 



individual 

 peptides 



individual 

 peptides 



individual 

 peptides 



