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Biochemistry, Biophysics, and Structural Biology
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
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Full-Text Articles in Life Sciences
Characterization Of An Axial Ligand Substitution In Sperm Whale Myoglobin, Michael J. Chen
Characterization Of An Axial Ligand Substitution In Sperm Whale Myoglobin, Michael J. Chen
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Of central importance to the study of heme proteins are the effects imposed by axial ligand(s) on the heme structure and, therefore, on the overall activity of the protein. In this study, we confirm and extend the spectroscopic characterization of a mutated sperm whale myoglobin in which the proximal Histidine is replaced with a Tyrosine residue (MbH93Y). The MbH93Y, as well as wild-type sperm whale myoglobin and horse erythrocyte catalase (HEC), was purified and characterized by optical absorption and x-ray absorption (XAS) spectroscopies. Optical absorption spectra of HEC and the metmyoglobin, cyanometmyoglobin, reduced, oxy, and carbon-monoxy forms of both sperm …
Extended X-Ray Absorption Fine Structure And Redox Potential Studies Of Heme-Substituted Horseradish Peroxidase And Myoglobin, Bing He
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Heme-substituted horseradish peroxidases and myoglobins were reconstituted from the apoenzyme using mesoheme and diacetyldeuteroheme. X-ray absorption spectroscopy was used to determine the dimensions of the active sites of these heme-substituted proteins, and were compared with those of the proto-hemeproteins. The change in the active-site structure corresponded with the electron withdrawing and donating effects of the different side chains. The oxidation-reduction potentials of Fe4+/Fe3+ couples of the heme-substituted proteins were measured at pH 7 with K2IrCl6. The oxidation-reduction potential sequence for compound I/compound II was diacetyldeutero- > proto- > meso- in horseradish peroxidase. The oxidation-reduction potential …