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 esta blish rigorously the appropriate molecular weight and amino acid seque nce. Liquid secondary ionization mass spectrometry produced the proton ated molecule ion, (M + H)(+), at m/z 981 of the endogenous peptide, a nd tandem mass spec trometry collected the product ion spectrum that c ontained the appropriate amino acid sequence-determining fragment ions produced from the precursor ion (M + H)(+). The amino acid sequence o f the peptide is YGGFLRRI.