試題詳解

22. A peptide was found to have a molecular mass of about 650 and upon hydrolysis produced Ala, Cys, Lys, Phe, and Val in a 1:1:1:1:1 ratio. The peptide upon treatment with Sanger's reagent produced DNP-Cys and exposure to carboxypeptidase produced valine. Chymotrypsin treatment of the peptide produced a dipeptide that contained sulfur and has a UV absorbance, and a tripeptide. Exposure of the peptide to trypsin produced a dipeptide and a tripeptide. Deduce the sequence of the peptide.
(A) Val-Ala-Lys-Phe-Cys
(B) Cys-Lys-Phe-Ala-Val
(C) Cys-Ala-Lys-Phe-Val
(D) Cys-Phe-Lys-Ala-Val
(E) Val-Phe-Lys-Ala-Cys