Date of Award:
5-1995
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Chemistry and Biochemistry
Committee Chair(s)
Linda S. Powers (Committee Chair)
Committee
Linda S. Powers
Committee
Kay Baker
Committee
Danny Blubaugh
Abstract
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 sequence for compound II/ferric was meso- > proto- > diacetyldeutero- in both HRP and myoglobin. These results indicate that the oxidation of ferric to ferryl form may be related to a radical mechanism. A net charge theory was also proposed to explain these results.
Checksum
71a51a0183e891f396d7ef185f1687b3
Recommended Citation
He, Bing, "Extended X-Ray Absorption Fine Structure and Redox Potential Studies of Heme-Substituted Horseradish Peroxidase and Myoglobin" (1995). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 7246.
https://digitalcommons.usu.edu/etd/7246
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