5] 



STUDIES ON PROTEIN MICROSTRUCTURE 



87 



Table 8 



PEPTIDES OF LYSINE ISOLATED FROM PARTIAL 



ACID HYDROLYSATES OF BOVINE CHYMO- 



TRYPSINOGEN AND TRYPSINOGEN 



particularly from the small number of different peptide sequences involving 

 cysteine^ detected in partial hydrolysates of trypsinogen, which contrasts 

 with the total number of cysteine (half-cystine) residues (11-13) present in 

 this protein. Finally, the results of our work on the arginine peptides may 

 prove of value in the concluding phases of the full structure determination 

 of the two proteolytic enzymes since they establish — unambiguously in the 

 case of chymotrypsinogen — the amino acid sequence at those very sites at 

 which fission of the peptide chains takes place in controlled enzymic hydro- 

 lysis. 



I should further like to give an account of some of our preliminary find- 

 ings in a comparison of the microstructure of two haemoglobins (horse and 

 hog) — proteins where, for practical reasons, we may not for the time being 

 expect an attack on the total structure. In this work we have so far con- 

 centrated on the comparison of the peptides of arginine^" and histidine^^ 

 (of which the haemoglobin molecule contains 14 and 36-38 residues, respec- 

 tively), and partly those of lysine. The isolation of the basic peptides from 

 partial hydrolysates of the globins prepared from pure, crystalline samples 

 of the haemoglobins was carried out by a combination of electrophoretic 



