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Wenkui Lan

Document Type

Thesis - University Access Only

Award Date

1990

Degree Name

Master of Science (MS)

Department / School

Chemistry

First Advisor

William S. Wadsworth, Jr.

Abstract

It has long been realized that free radicals are detrimental to biological processes. 1-5 Indeed, free radicals have been implicated in the aging process as well as suspect in carcinogenesis 6-10. Direct evidence has recently been obtained for adduct formation of DNA catalyzed by free radicals.11 DNA naturally wraps around protein in nucleosomes, a chromosome's smallest unit. When such pairing are exposed to hydroxyl radicals both the DNA and protein spawn new radicals as reactive molecular fragments containing an unpaired electron. Seeking to find mates for their unpaired electrons, these link up with adjacent biological material yielding DNA-protein crosslinks. Such protein adducts of DNA have been directly observed by GC-MS which confirms long held beliefs that such free radical catalyzed adduct formation does occur and is a direct cause of mutations. Free radicals, regardless of their sources, by catalyzing DNA-adduct formation damage living cells. In order to prevent cell damage, it is required that free radical formation be depressed which leads to the additional requirement that a knowledge of the source of free radicals be accumulated. Unfortunately, free radicals are formed naturally from a variety of sources especially from natural or man-made radiation (i.e. gamma radiation). Oxygen itself in its natural triplet state can promotes radical formation although biological systems in this case appear to have a natural detens mechanism. Other naturally occurring [sic] molecules may also be free radical promoters especially under conditions of stress. It is one such system, and indeed one which is universally present that is the focus of this proposal. A study of its chemistry with emphasis on conditions under which it can promote free radical formation is our goal. The objective of my thesis is to determine if free radical formation can occur under mild conditions by hemolytic decomposition of a compound whose structure closely resembles one found in nature. The compounds of interest are synthetic analogues of acetyl phosphates. Another object is to determine why these compounds are so extremely reactive and how their naturally occurring counterparts react. We have discovered in this research that acylphosphates may decompose homolytically to give free radicals. In consideration of the importance of free radicals in biological systems, our discovery could have important consequences.

Library of Congress Subject Headings

Phosphates
Dissociation
Free radicals (Chemistry)
Isomerization

Format

application/pdf

Number of Pages

92

Publisher

South Dakota State University

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