Persistent Link:
http://hdl.handle.net/10150/187891
Title:
IRON PORPHYRIN MODELS OF BIOLOGICAL ELECTRON TRANSFER PROTEINS.
Author:
ROOT, DOUGLAS PAUL.
Issue Date:
1984
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The axial ligands of the iron porphyrin in Cytochrome c, an electron transfer protein, are an imidazole group of a histidine residue and a methionine thioether. This ligand coordination sphere has been difficult to model and consequently the influence of these ligands on the properties of cytochrome c has been problematic. The electrochemical and spectroscopic study of a novel strapped porphyrin has been addressed toward this problem. Spectroscopic studies have demonstrated the ability of this porphyrin to hold a thioether ligand near the central metal atom. The influence of the thioether is not seen in the UV/visible spectrum of the iron complex of this porphyrin. The coordination of N-methyl imidazole to the iron complexes of several porphyrins has been studied by UV/visible spectroscopy. These studies indicate a reduced affinity of the strapped porphyrin for this ligand. Also, the oxidation products of several porphyrins were monitored by thin-layer spectroelectrochemistry. Cyclic voltammetry has been used to demonstrate the influence of the thioether on the Fe('+3)/Fe('+2) electron transfer reaction. It was found that the thioether stabilizes the lower oxidation state causing an anodic shift in the half-wave potential for the reaction. However, the stabilization seen with this model system is not sufficient to account for the large positive redox potential of Cytochrome c. The oxidations of a selected group of free base and metallo- porphyrins were also studied. It was found that the oxidation of strapped porphyrins was similar in many respects to those of non-strapped porphyrins. The notable acception to this generalization was the instability of the cation radical of the strapped porphyrins used in this work.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Porphyrins.; Electron transport.; Oxidation-reduction reaction.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Chemistry; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Wilson, George S.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleIRON PORPHYRIN MODELS OF BIOLOGICAL ELECTRON TRANSFER PROTEINS.en_US
dc.creatorROOT, DOUGLAS PAUL.en_US
dc.contributor.authorROOT, DOUGLAS PAUL.en_US
dc.date.issued1984en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe axial ligands of the iron porphyrin in Cytochrome c, an electron transfer protein, are an imidazole group of a histidine residue and a methionine thioether. This ligand coordination sphere has been difficult to model and consequently the influence of these ligands on the properties of cytochrome c has been problematic. The electrochemical and spectroscopic study of a novel strapped porphyrin has been addressed toward this problem. Spectroscopic studies have demonstrated the ability of this porphyrin to hold a thioether ligand near the central metal atom. The influence of the thioether is not seen in the UV/visible spectrum of the iron complex of this porphyrin. The coordination of N-methyl imidazole to the iron complexes of several porphyrins has been studied by UV/visible spectroscopy. These studies indicate a reduced affinity of the strapped porphyrin for this ligand. Also, the oxidation products of several porphyrins were monitored by thin-layer spectroelectrochemistry. Cyclic voltammetry has been used to demonstrate the influence of the thioether on the Fe('+3)/Fe('+2) electron transfer reaction. It was found that the thioether stabilizes the lower oxidation state causing an anodic shift in the half-wave potential for the reaction. However, the stabilization seen with this model system is not sufficient to account for the large positive redox potential of Cytochrome c. The oxidations of a selected group of free base and metallo- porphyrins were also studied. It was found that the oxidation of strapped porphyrins was similar in many respects to those of non-strapped porphyrins. The notable acception to this generalization was the instability of the cation radical of the strapped porphyrins used in this work.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPorphyrins.en_US
dc.subjectElectron transport.en_US
dc.subjectOxidation-reduction reaction.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorWilson, George S.en_US
dc.identifier.proquest8505239en_US
dc.identifier.oclc693590957en_US
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