84 F. §ORM [5 



been given here more particularly for the reason that this method might 

 have some justification in the comparison of highly complex proteins where 

 there is no possibility of isolating and identifying a reasonable proportion 

 of individual peptides. In our further work on the cysteic acid peptides of 

 chymotrypsinogen and trypsinogen* we undertook the isolation and identi- 

 fication of individual peptides. For this purpose we used a cysteic peptide 

 fraction obtained by oxidizing the neutral peptide fraction, isolated by elec- 

 trophoresis in a five-compartment apparatus, with performic acid; the 



Table 6 



CYSTEIC ACID PEPTIDES ISOLATED FROM PARTIAL ACID 

 HYDROLYSATES OF BOVINE CHYMOTRYPSINOGEN AND 



TRYPSINOGEN 



* Actually, trypsin was used in these experiments since it differs from the enzymogen 

 by a peptide sequence irrelevant to this particular study. 



