Answer to Question #90950 in Biochemistry for Sankalp pathak

Question

. Treatment of a polypeptide by 2-mercaptoethanol yields two polypeptides that
have the following amino acid sequences:
X: Ala-Phe-Cys-Met-Tyr-Cys-Leu-Trp-Cys-Asn
Y: Val-Cys-Trp-Val-Ile-Phe-Gly-Cys-Lys
Chymotrypsin-catalyzed hydrolysis of the intact polypeptide yields polypeptide
fragments with the following amino acid compositions:
(Ala, Phe) (Asn, Cys2, Met,Tyr) (Cys, Gly, Lys) (Cys2, Leu,Trp2,Val) (Ile, Phe,Val)
Indicate the positions of the disulfide bonds in the original polypeptide. Cysteines are
numbered in order (C1, C2, C3 in X; and C4, C5 in Y).

Answer 1

There are two disulfide bonds in the intact protein:

1. C1-C3
2. C2-C4