BARBARA W. LOW AND JOHN T. EDSALL 



The peptide derived from conversion of ovalbumin into plakalbumin (76) 

 Ala.Gly.Val.Asp.Ala.Ala 



^-Corticotropin Ser . Tyr . Ser . Met . GIu . His . Phe . Arg . Try . Gly . Lys . Pro 



1 2 3 4 5 6 7 8 9 10 11 12 



Val . Gly . Lys . Lys . Arg . Arg . Pro . Val . Lys . Val . Tyr . Pro . . . 

 13 14 15 16 17 18 19 20 21 22 23 24 



NH2 



I 

 Asp. Gly. Ala. Glu. Asp. GIu. Leu. Ala. GIu. Ala. Phe. Pro. . . 

 25 26 27 28 29 30 31 32 33 34 35 36 



Leu. GIu. Phe. 

 37 38 39 



Comparison of Corticotropins 



In addition to pig jS-corticotropin (12,48a) as shown above, sequences 

 for sheep a-corticotropin (60a) and pig corticotropin A (108a) have also been 

 reported. All are made up of a single chain sequence of 39 amino acid residues, 

 and the sequence appears to be identical for all three except within the seg- 

 ment of residues 25-33 inclusive. The comparison of the residue sequence for 

 these residues in the three corticotropins is shown below. Note that the 

 composition of the sequence 25-28 is the same in all cases; only the order differs. 

 There appears still to be a little uncertainty about the order, especially in the 

 case of corticotropin A. 



Residue no. 25 26 27 28 29 30 31 32 33 



Sheep a-corticotropin* Ala.GIy.Glu.Asp.Asp.GIu. Ala.Ser.GIu 



Pig corticotropin A Gly.AIa.GIu.Asp.Asp.Glu. Leu. Ala. Glu 



Pig /3-corticotropin Asp.Gly.AIa.Glu.Asp.Glu.NH2.Leu.Ala.GIu 



* There are two amide groups in a-corticotropin, but the particular 

 Asp. or GIu. residues with which they are associated are still undetermined. 



We employ for the amino acid residues the now indispensable abbreviated 

 notation which was originated by the late Dr. Erwin Brand and set forth in a 

 review by Brand and Edsall (20) and later by Sanger (92). Each amino acid 

 residue is denoted by the first three letters of its name, except for isoleucine 

 (lieu), cysteine (CySH), and a half cystine residue (CyS — ). Asparagine and 

 glutamine residues are denoted by Asp.NH2 and GIU.NH2, respectively. 

 An jV-terminal residue, with a free a-amino group, is by convention written 

 at the left-hand end of the formula. All optically active amino acid residues 

 are to be taken as having the l configuration in these formulas. 



384 



