Publication Date

1995

Document Type

Dissertation/Thesis

First Advisor

Erman, James E.

Degree Name

M.S. (Master of Science)

Department

Department of Chemistry

LCSH

Myoglobin||Hydrogen-ion concentration||Hydrogen peroxide

Abstract

The kinetics of the bimolecular reaction between metmyoglobin and hydrogen peroxide were studied through the use of stopped-flow techniques. The reactions were performed within the pH range of 5.0 to 11.0 in buffer solutions having ionic strengths of 0.10 M. The reactions were studied under pseudo-first order conditions with hydrogen peroxide present in excess, in one case, and with metmyoglobin present in excess, in another case. Second order rate constants were calculated frotn the slope of the lines constructed from plots of observed pseudo-first order rate constants versus concentrations of hydrogen peroxide. The rate constants of the reaction were independent of the pH of the reaction within the pH range of 5.0 to 8.5, but within the pH range of 8.5 to 11.0, the rate constants of the reaction decreased with increasing pH. The pH dependence of the rate constants for the reaction between metmyoglobin and hydrogen peroxide was fit to a mechanism involving a single pK, in the protein. From the spectra of metmyoglobin, taken in buffers prepared at pH values within the entire range of the protein’s stability, there appeared to be two different forms of metmyoglobin. One form existed at pH below 8.5 and the other form existed above pH of 8.5. The acidic form of metmyoglobin reacts with hydrogen peroxide with a rate of 315 ± 15 M'V1, while the alkaline form of metmyoglobin was unreactive. The transition from the acidic form to the basic form occurred at approximately pH 9.5.

Comments

Includes bibliographical references (pages [58]-59)

Extent

x, 95 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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