Graduation Year

2008

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Chemistry

Major Professor

Li-June Ming, Ph.D.

Committee Member

Steven H. Grossman, Ph.D.

Committee Member

Kirpal S. Bisht, Ph.D.

Committee Member

Peter Zhang, Ph.D.

Committee Member

Jun Tan, M.D., Ph.D.

Keywords

amyloid-β, bacitracin, histatin 5, copper (II), oxygen, catechol oxidation, antimicrobial peptides, Alzheimer's disease, hydrogen peroxide, kinetics, NMR spectroscopy

Abstract

Copper is one of the essential metal ions for aerobic organisms. Two well known functions of copper in the biological systems are electron transfer and molecular oxygen interaction. Thus, this metal can be found in haemocyanin, an oxygen carrier protein, and superoxide dismutase, an enzyme that involves in electron transfer. In addition, having a positive redox potential allows copper to be involved in redox chemistry. It is the redox properties of copper that are responsible for many important biochemical processes. Although the copper-containing oxidases have been well studied over the years, certain mechanistic details such as reaction intermediates remain to be elucidated. Several research groups have been trying to study this by trying to mimic the native systems, synthesizing bulky organic molecules with copper-binding and oxidative capabilities. However, these model systems are only applicable in organic solvents at low temperatures. In this study, three naturally occurring peptides, amyloid-ß, bacitracin, and histatin 5, have been shown to display the oxidative chemistry when complexed with CuII. A combination of spectroscopic (UV-Vis and NMR) and reactivity was used in studying their metal-binding properties as well as in elucidating their catalytic mechanism.

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