Intrinsic chemistry of peptide ions: Field desorption and collision-induced decomposition of bradykinin

The field desorption mass spectrum of bradykinin and collision-induced decomposition spectra of ions formed from bradykinin during field desorption are reported. Low-energy fragmentation pathways of bradykinin are identified. It is proposed that bradykinin can undergo rearrangement to a novel ion structure, characterized by a propensity for cleavage at one specific site within the peptide.