The following data were collected on the structure of a polypeptide chain. Total

The primary structure of the protein would be: Gly-Ile-Val-Glu-Glu- Cys-Cys-Ala -Ser-Val-Cys-Ser-Leu-Tyr-Glu- Leu-Glu-Asp-Tyr-Cys-Asp

ID: 863289 • Letter: T

Question

The following data were collected on the structure of a polypeptide chain. Total hydrolysis gave Gly, Ala, Val2, Leu2, Ile, Cys4,

Asp2, Glu4, Ser2, Tyr2. Treatment of the intact chain with 2.4-dinitrofluorobenzene followed by acid hydrolysis gave 2.4-

dinitrophenylglycine; treatement with carboxypeptidase yielded free aspartate as the first product. Partial hydrolysis gave several

oligopeptides. Edman degradation of each yielded the following: Cys-Cys-Ala, Glu-Asp-Tyr, Glu-Glu-Cys, Glu-Leu-Glu, Cys-

Asp, Tyr-Cys, Ser-Val-Cys, Glu-Cys-Cys, Leu-Tyr-Glu, Gly-Ile-Val-Glu-Glu. Cleavage with chymotrypsin yielded a peptide that

on hydrolysis gave Ser-Val-Cys and Ser-Leu-Tyr. Provide a structure for this protein that is consistent with the data.

The primary structure of the protein would be:

Gly-Ile-Val-Glu-Glu- Cys-Cys-Ala -Ser-Val-Cys-Ser-Leu-Tyr-Glu- Leu-Glu-Asp-Tyr-Cys-Asp

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