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The total number of fragments generated by the complete and sequential cleavage of the polypeptide given below by Trypsin followed by CNBr is _______
Phe-Trp-Met-Gly-Ala-Lys-Leu-Pro-Met-Asp-Gly-Arg-Cys-Ala-Gln
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- 1
- 3
- 5
- 7
Correct Option: C
Given sequence: Phe-Trp-Met-Gly-Ala-Lys-Leu-Pro-Met-Asp-Gly-Arg-Cys-Ala-Gln
First it is digested with Trypsin and than with Cyanogen Bromide in a process of sequential cleavage. Cyanogen bromide hydrolyzes peptide bonds at the C-terminus of methionine residues. Trypsin cleaves peptide chains mainly at the carboxyl side of the amino acids lysine or arginine, except when either is followed by proline.
After trypsin digestion, fragments generated are:
Phe-Trp-Met-Gly-Ala-Lys; Cys-Ala-Gln; Leu-Pro-Met-Asp-Gly-Arg
After CNBr digestion, the fragments generated are:
Phe-Trp-Met; Gly-Ala-Lys; Cys-Ala-Gln; Leu-Pro-Met; Asp-Gly-Arg
