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Dissertation
Hemoproteins: reactivity and spectroscopy
Doctor of Philosophy (Ph.D.), Drexel University
Oct 1989
DOI:
https://doi.org/10.17918/D80373
Abstract
Human hemoglobin, myoglobin, Glycera dibranchiata, elephant, hemoglobins derivatives, and model iron(II) and iron(III) porphyrins such octaethylporphyrin (OEP) have been prepared and characterized by ESR and optical spectroscopy. Kinetics, thermodyamics, binding and optical studies are employed to investigate the influence of the heme environment on the reactivity and electronic properties of the active site. The kinetics of the autoredox process of nitrosyliron(III) hemoproteins were followed in detail, and the activation parameters [delta]H[double dagger] and [delta]S[double dagger] were determined. The thermochromism of myoglobin and Glycera dibranchiata hemoglobin derivatives and of cytochrome-c were monitored. Two different groups of behavior were identified. The first group shows equilibria between two spin states, while the second group is associated with globin conformation changes. Enthalpy-entropy compensation is presented by all these heme derivatives. The isothermal binding affinities of Glycera dibranchiata hemoglobin for heterocyclic amines and other ligands have been evaluated and compared to those of myoglobin. The interactions between the environment and the axial ligand determine the ligand affinity of myoglobin, while the electronic properties of the axial ligand control the binding affinities of Glycera hemoglobin. The heterotropic effectors influence the heme ligation affinities. A comparative analysis of the electronic, circular dichroism and Kuhn anisotropy spectra of heme protein nitrosyls has been carried out in order to identify the relationship between the environment and the electronic structure of the active site. The anisotropy factor of a transition, g, was used here to assign some of the electronic transition.
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Details
- Title
- Hemoproteins
- Creators
- Joseph J. Stephanos - DU
- Contributors
- Anthony William Addison (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Science (1970-1990); Drexel University
- Other Identifier
- 8169; 991014632432204721