This peptide is amino acids 17 to 26 fragment of p53, the Mdm-2 binding domain of p53 known also as p53N. This sequence contains all of the residues that contact the binding domain of Mdm-2. The tumor suppressor protein p53 is important in maintaining genome stability and in preventing cancer development.
Pyroglutamyl (pGlu) peptides may spontaneously form when either Glutamine (Q) or Glutamic acid (E) is located at the sequence N-terminus. The conversion of Q or E to pGlu is a natural occurrence and in general it is believed that the hydrophobic γ-lactam ring of pGlu may play a role in peptide stability against gastrointestinal proteases. Pyroglutamyl peptides are therefore considered a normal subset of such peptides and are included as part of the peptide purity during HPLC analysis.