Dissociation reactions of gaseous ferro-, ferri-, and apo-cytochrome c ions.
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.
Wells
J M
JM
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393, USA.
Reid
G E
GE
Engel
B J
BJ
Pan
P
P
McLuckey
S A
SA
D001059:Apoproteins / Q000737:chemistry*; D003574:Cytochrome c Group / Q000737:chemistry*; D045304:Cytochromes c; D004563:Electrochemistry; D006418:Heme / Q000737:chemistry; D010084:Oxidation-Reduction
D001059:Apoproteins; D003574:Cytochrome c Group; D006418:Heme; D045304:Cytochromes c