DYNORPHIN A(1-8) IN HUMAN PLACENTA - AMINO-ACID-SEQUENCE DETERMINED BY TANDEM MASS-SPECTROMETRY

Presence of the kappa receptor-preferring neuropeptide dynorphin A(1-8) in human placenta has been demonstrated by mass spectrometry to establish rigorously the appropriate molecular weight and amino acid sequence. Liquid secondary ionization mass spectrometry produced the protonated molecule ion, (M + H)(+), at m/z 981 of the endogenous peptide, and tandem mass spec trometry collected the product ion spectrum that contained the appropriate amino acid sequence-determining fragment ions produced from the precursor ion (M + H)(+). The amino acid sequence of the peptide is YGGFLRRI.