Thesis (M.S.)--Eastern Illinois University, 2009. / Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2002. / Title from first page of PDF file. Document formatted into pages; contains xix, 173 p. Includes abstract and vita. Advisor: Michael K. Chan, Dept. of Biochemistry. Includes bibliographical references (p. 163-173).

No description available.

The superoxide dismutases (SODs) are a family of metalloproteins that catalyse the disproportionation of the toxic superoxide anion into hydrogen peroxide and oxygen. The iron-coordinating SOD of Mycobacterium tuberculosis is an ideal candidate for structure-function analysis by site-directed mutagenesis and X-ray crystallographic techniques. Comparison of the previously determined M. tuberculosis structure with other known SOD structures and mycobacterial SOD sequences highlighted candidate residues for mutagenesis to study their roles in areas of interest, both to the enzyme family and the intracellular survival of the bacterium, the causal agent of tuberculosis. Individual members of the SOD family are generally only active with either iron or manganese as the catalytic ion, despite high conservation of the active site. Histidine 145 was highlighted as a potential discriminating residue, with the residue being glutamine in the closely related M. leprae manganese-SOD. Mutation to glutamine did not alter the metal ion specificity, although mutation to glutamate produced a manganese-binding M. tuberculosis mutant. These findings suggest that the charge of the residue in this position plays a role in metal ion deternlination. The 88 kD tetramer is compact in nature, primarily due to novel dimer-dimer interactions. A serine residue (123) that hydrogen bonds to the corresponding residue in the neighbouring monomer was mutated to cysteine in an attempt to produce a stabilising disulphide bridge. Although the presence of a disulphide bridge was demonstrated, there was a slight reduction in stability of the mutant compared to the wild type enzyme, presumably owing to unfavourable dihedral angles.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xi, 98 p.; also includes graphics. Includes bibliographical references (p. 93-98). Available online via OhioLINK's ETD Center

No description available.

No description available.

No description available.

In this work, the chemical preparation and characterization of an isotopically enriched superoxide dismutase (SOD) is described. Its evaluation as a standard in species-specific isotope dilution analysis by HPLC coupled to ICP-MS is carefully evaluated. The proposed method involved the removal of the enzyme's metal co-factors under various conditions and their replacement with isotopically enriched ⁶⁵Cu and ⁶⁸Zn. SEC-ICP-MS showed that the prepared enriched enzymes had a different metal isotopic abundance compared to the wild-type enzyme. Isotopically enriched and wild-type SOD showed the same migration pattern in 1D-PAGE. An enzyme activity assay provided evidence that incorporated ⁶⁵Cu was bound to the correct SOD-binding motif, since the measured activity correlated directly with the amount of Cu present in the prepared enzyme. The addition of free Cu and Zn or a metal chelator did not result in any exchange or loss of metals from the enzyme at neutral pH. Striking experiments were undertaken to evaluate the use of isotopically enriched SOD in SS-IDMS. The chemical preparation study on SOD was further extended to prepare various other isotopically enriched metalloproteins, including carbonic anhydrase, ceruloplasmin, transferring and haemoglobin. Various enrichment procedures were conducted and their performances then evaluated, using SEC-ICP-MS and protein assays. A procedure for the quantification of SOD in tissue samples using an isotopically enriched SOD spike in combination with 2-dimensional HPLC and SS-IDMS was developed and assessed. The feasibility of employing isotopically enriched protein spikes for the speciation of metalloproteins by utilising gel electrophoresis and LA-ICP-MS was also investigated. Furthermore, the change of the iron speciation of the meat-containing protein myoglobin after various treatments was examined using a combination of SEC-ICP-MS and ESI-MS.

by Ng King-man. / Bibliography: leaves 87-89 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1986