PHPFHFFVYK

NCCCC[C@@H](C(O)=O)NC([C@H](CC1=CC=C(O)C=C1)NC([C@H](C(C)C)NC([C@H](CC2=CC=CC=C2)NC([C@H](CC3=CC=CC=C3)NC([C@H](CC4=CNC=N4)NC([C@H](CC5=CC=CC=C5)NC([C@H]6N(C([C@H](CC7=CNC=N7)NC([C@H]8NCCC8)=O)=O)CCC6)=O)=O)=O)=O)=O)=O)=O

[1]V Katta, et al. Use of a single-quadrupole mass spectrometer for collision-induced dissociation studies of multiply charged peptide ions produced by electrospray ionization. Anal Chem. 1991 Jan 15;63 (2) :174-8.