Lipid Peroxidation-Dependent Chemiluminescence from the Cyclization of Alkylperoxyl Radicals to Dioxetane Radical Intermediates

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• 作者：Graham S. Timmins ; Rosemeire E. dos Santos ; Adrian C. Whitwood ; Luiz H. Catalani ; Paolo Di Mascio ; Bruce C. Gilbert ; and Etelvino J. H. Bechara
• 刊名：Chemical Research in Toxicology
• 出版年：1997
• 出版时间：October 1997
• 年：1997
• 卷：10
• 期：10
• 页码：1090 - 1096
• 全文大小：163K
• 年卷期：v.10,no.10(October 1997)
• ISSN：1520-5010

文摘

This work reveals a novel mechanism for triplet carbonylformation (and hence chemiluminescence) during lipid peroxidation, whose chemiluminescence has beenattributed to bothtriplet carbonyls and singlet oxygen. As a model forpolyunsaturated fatty acid hydroperoxides,we have synthesized 3-hydroperoxy-2,3-dimethyl-1-butene byphotooxygenation of tetramethylethylene. One-electron oxidation of this hydroperoxide with hemeproteins and peroxynitriteto the corresponding alkylperoxyl radical results in chemiluminescence,both direct and 9,10-dibromoanthracene-2-sulfonate-sensitized, the latter attributed to theformation of tripletacetone. It is postulated that triplet acetone results from thecyclization of the alkylperoxylradical to a dioxetane radical intermediate followed by itsthermolysis. This is supported byEPR spin-trapping experiments in which discrimination betweencarbon-centered radicalsderived from the alkyloxyl and alkylperoxyl radicals is achievedthrough the use of one-electronoxidants and reductants, e.g., Fe^II andTi^III.