F, SANGER 



From the study of partial hydrolyzates of fraction A obtained 

 by the action of acid, pepsin, and chymotrypsin the sequence 

 indicated in Figure 2 was deduced (18,19). Hydrolyzates ob- 

 tained by the action of papain and a mold protease were also 

 studied, largely in connection with the location of amide resi- 



30 - 



<j> 



z 20|- 



a: 

 o 



o 



cr 



Li. 



UJ 

 O 



CO 



10 - 



CO CySOjH.CySOjH 

 (//^ Cysteic acid 



C^ Glu.CySOaH.CySOjH 



C } cysO3H.cysO3H.Aia. 

 <0 6iu.cys03H.cys03H.Aia. 



s 



CyS03H.Asp. 

 Glu.CyS03H 



C^ Vol.CySOjH + Glu.Glu.CySOaH 



dD CyS03H.AIa. 



CD Tyr.CySOjH 



C J Ser.Vol.CySOjH 



Olleu Val.Glu.Glu.CySOaH 

 + Gly.Ileu.Val.Glu.Glu.CySOjH 



Q ) Aspartic acid 



Other peptides 



Fig. 3. lonophoresis of acid hydrolyzate of fraction A at 

 ^H 3.3 and 1500 v. (2 hours). 



dues and also with the purpose of confirming the structure. 

 From Figure 2 it can be seen that these two latter enzymes ex- 

 hibit a rather wide specificity, resembling in some ways the 

 action of pepsin, though definitely different in detail. An un- 

 expected finding was that the bond CySOsHSer (A, 11-12) was 

 split by chymotrypsin. The only other susceptible bonds are 



448 



