title: Michael addition of acrolein to lysinyl and N-terminal residues of a model peptide: targets for cytoprotective hydrazino drugs.
abstract: The antihypertensive drug hydralazine blocks acrolein-mediated toxicity by trapping both free aldehyde- and acrolein-adducted proteins, with the latter property more closely related to cytoprotection in cellular models. Here we report the identification of products from 'protein adduct-trapping' reactions using electrospray ionisation mass spectrometry (ESI-MS). Reaction of a 13-residue peptide containing a single lysine with acrolein for 30 min generated ions corresponding to mono- and bis-Michael-adducted peptides. An ion corresponding to a cyclic species formed from bis-adducted lysine was conspicuous at later times (60, 180 min). Tandem mass spectrometric (MS/MS) analysis revealed Michael adduction also occurred on the N-terminus, with a novel N-terminal (3-formyl-3,4-dehydropiperidino) species formed on this residue. Addition of hydralazine to acrolein-adducted peptides generated a diverse range of hydrazones that were also characterised by MS/MS analysis. The results confirm that mass spectrometry is a powerful tool for characterising the reactions of noxious electrophiles with biological macromolecules.
authors.affiliation: Discipline of Chemistry, School of Chemistry and Physics, The University of Adelaide, Adelaide, Australia, 5005.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Kaminskas
authors.forename: Simon M
authors.initials: SM
authors.lastname: Pyke
authors.forename: Philip C
authors.initials: PC
authors.lastname: Burcham
mesh_terms: D000171:Acrolein / Q000737:chemistry*; D001665:Binding Sites; D019610:Cytoprotection; D016503:Drug Delivery Systems / Q000379:methods*; D006834:Hydrazines / Q000737:chemistry*; D008239:Lysine / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D006834:Hydrazines; D010455:Peptides; D000171:Acrolein; D008239:Lysine