Structural Basis for Chloroperoxidase Catalyzed Enantioselective Epoxidations and Mechanisms of Selected Anticancer Drug Induced Apoptosis
Doctor of Philosophy (PhD)
First Advisor's Name
First Advisor's Committee Title
Second Advisor's Name
Second Advisor's Committee Title
Third Advisor's Name
Stanislaw F. Wnuk
Third Advisor's Committee Title
Fourth Advisor's Name
Manuel Alejandro Barbieri
Fourth Advisor's Committee Title
biotechnology, cell biology, medicinal chemistry and pharmaceutics, pharmacology
Date of Defense
Chloroperoxidase (CPO), a member of the heme peroxidase family, has diverse catalytic activities toward a broad range of substrates. In addition to catalyzing halogenation reactions involved in the biosynthesis of halogen-containing compounds, CPO also catalyzes reactions typical of traditional heme peroxidases, catalases, and cytochrome P450 enzymes. Despite the powerful and versatile catalytic activity of CPO, its applications have been thwarted by the difficulty in regenerating the active enzyme and substrate (peroxide) induced protein inactivation. To overcome these shorting comings of the protein, we investigate the fabrication and characterization of chloroperoxidase (CPO) and glucose oxidase (GOx) on the surface of MGO. The performance of the immobilized CPO was considerably enhanced by coupling with GOx that provided the required H2O2 in situ through glucose oxidation. The activity of MGO-GOx-CPO (96.6%) towards the decolorization of orange G was much superior to that of MGO-GOx+MGO-CPO (86.2%), probably as a result of reduced mass transfer resistance between CPO and H2O2 generated from GOx molecules. MGO-GOx-CPO can be conveniently reused for its ease of recovery in the presence of an external magnetic field, with ∼38.5% activity remained after 6 cycles of applications. The work detailed in Chapter 2 of this dissertation demonstrates the feasibility of co-immobilizing CPO and GOx onto MGO and the potential of MGO-GOx-CPO in environmental applications.The versatility of CPO has long been attributed to the unique structural components of the protein environment that constitute the heme active site, particularly the identity of the axial heme ligand and amino acid residues distal to the heme iron. The heme active site structure has also been thought to be responsible for the enantioselectivity of CPO. Chapter 3 of my dissertation investigates the structural factors that contribute to CPO’s stereoselectivity in catalyzing epoxidation reactions. The characterization of CPO-substrate complex will be carried out using UV-Vis spectrophotometry and nuclear magnetic resonance (NMR) spectroscopy. We will focus on understanding the mechanism of CPO-catalyzed enantioselective epoxidation and structure-activity relationship of CPO.
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Guo, Yongjian, "Structural Basis for Chloroperoxidase Catalyzed Enantioselective Epoxidations and Mechanisms of Selected Anticancer Drug Induced Apoptosis" (2019). FIU Electronic Theses and Dissertations. 4312.
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