title: Characterization of heme c peptides by mass spectrometry.
abstract: Liquid secondary ion mass spectrometry, also called fast atom bombardment mass spectrometry, has been used to determine proteolytic hydrolysis sites for peptides derived from c-type cytochromes that contain covalently attached heme c. An unexpected fragmentation occurs that breaks the covalent thioether bonds between the heme and the peptide, and the heme fragment further rearranges to give rise to an intense ion at m/z of 617 that corresponds to protonated iron protoporphyrin IX. The observation of this ion fragment can be used to unambiguously identify the presence of authentic heme c in peptides or peptide mixtures at the subnanomole level.
authors.affiliation: Department of Chemistry, University of Alabama, Tuscaloosa 35487-0336.
authors.forename: A D
authors.initials: AD
authors.lastname: Carraway
authors.forename: R S
authors.initials: RS
authors.lastname: Burkhalter
authors.forename: R
authors.initials: R
authors.lastname: Timkovich
authors.forename: J
authors.initials: J
authors.lastname: Peterson
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001665:Binding Sites; D003574:Cytochrome c Group / Q000737:chemistry*; D006418:Heme / Q000031:analogs & derivatives* / Q000737:chemistry; D006868:Hydrolysis; D008969:Molecular Sequence Data; D011190:Potassium Cyanide / Q000494:pharmacology; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D000596:Amino Acids; D003574:Cytochrome c Group; C031690:heme C; D006418:Heme; D011190:Potassium Cyanide