Which of the following fragments would not result when the decapeptide Asn-Gly-Lys-Phe-Pro-Arg-Gly-Leu-Lys-Ser is treated with trypsin?

A) Gly-Leu-Lys
B) Phe-Pro-Arg
C) Asn-Gly-Lys
D) Pro-Arg-Gly-Leu

When treated with trypsin, the amino acid bonds are cleaved on the carboxyl side of lysine (K) or arginine (R) residues. Therefore, based on the sequence of the decapeptide, fragment D Pro-Arg-Gly-Leu would not result from trypsin treatment because the bond between Arginine (Arg) and Glycine (Gly) would not be cleaved by trypsin, as there is no Lysine or Arginine residue within the fragment. The other fragments would result from trypsin treatment as they contain either a lysine or arginine residue at the cleavage site.