title: Dissociation reactions of gaseous ferro-, ferri-, and apo-cytochrome c ions.
abstract: Electrochemical reduction of the iron bound in the heme group of cytochrome c is shown to occur in the nano-electrospray capillary if the protein is sprayed from neutral water using a steel wire as the electrical contact. Quadrupole ion trap collisional activation is used to study the dissociation reactions of cytochrome c as a function of the oxidation state of the iron. Oxidized (Fe(III)) cytochrome c dissociates via sequence-specific amide bond cleavage, while the reduced (Fe(II)) form of the protein dissociates almost exclusively by loss of protonated heme. Apo-cytochrome c, from which the heme has been removed either via gas-phase dissociation of the reduced holo-protein or via solution chemistry, dissociates via amide bond cleavage in similar fashion to the oxidized holo-protein.
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Wells
authors.forename: G E
authors.initials: GE
authors.lastname: Reid
authors.forename: B J
authors.initials: BJ
authors.lastname: Engel
authors.forename: P
authors.initials: P
authors.lastname: Pan
authors.forename: S A
authors.initials: SA
authors.lastname: McLuckey
mesh_terms: D001059:Apoproteins / Q000737:chemistry*; D003574:Cytochrome c Group / Q000737:chemistry*; D045304:Cytochromes c; D004563:Electrochemistry; D006418:Heme / Q000737:chemistry; D010084:Oxidation-Reduction
chemical_list: D001059:Apoproteins; D003574:Cytochrome c Group; D006418:Heme; D045304:Cytochromes c