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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
12
|
| pubmed:dateCreated |
1992-7-27
|
| pubmed:abstractText |
The oxidation chemistry and biochemistry of the serotonergic neurotoxin 5,7-dihydroxytryptamine (1) has been studied under anaerobic and aerobic conditions in aqueous solution at physiological pH. Under anaerobic conditions, one-electron oxidants (ferricytochrome c, peroxidase/H2O2, ceruloplasmin, Cu2+) generate a radical intermediate. Dimerization of the C(6)-centered resonance form of this radical followed by secondary oxidations yields 3-(2-aminoethyl)-6-[3-(2-aminoethyl)-1,7-dihydro- 5-hydroxy-7-oxo-6H-indol-6-ylidene]-1-H-indole-5,7(4H,6H)-dione. Under aerobic conditions, molecular O2 attacks the C(4)-centered 1 radical to yield a hydroperoxy radical which decomposes to 5-hydroxytryptamine-4,7-dione (2). Autoxidation of 1 proceeds by primary attack by molecular O2 on a C(4)-centered carbanion to form a superoxide-radical complex. This rearranges to a C(4)-centered hydroperoxide which decomposes to 2. A C(6)-centered carbanion of 1 combines with 2 to give, ultimately, 6,6'-bi-5-hydroxytryptamine-4,7-dione (3). Trace concentrations of transition metal ions (Fe3+, Fe2+, Cu2+, Mn2+) catalyze the autoxidation of 1 by catalytic cycles in which a hydroperoxide intermediate plays key roles. A byproduct of the transition metal-catalyzed oxidation of 1 is superoxide, O2-. Because of its enormous basicity O2- facilitates deprotonation of 1. The C(4)-centered carbanion so produced is oxidized by molecular O2 or by the hydroperoxy radical (HO2) to give radical intermediates and thence 2 and 3. Mechanistic pathways leading to the various products of oxidation of 1 are proposed and the potential roles of oxidation reactions of the indolamine are related to its neurodegenerative properties.
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| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/5,7-Dihydroxytryptamine,
http://linkedlifedata.com/resource/pubmed/chemical/Catalase,
http://linkedlifedata.com/resource/pubmed/chemical/Ceruloplasmin,
http://linkedlifedata.com/resource/pubmed/chemical/Cytochrome c Group,
http://linkedlifedata.com/resource/pubmed/chemical/Hydrogen Peroxide,
http://linkedlifedata.com/resource/pubmed/chemical/Hydroxides,
http://linkedlifedata.com/resource/pubmed/chemical/Hydroxyl Radical,
http://linkedlifedata.com/resource/pubmed/chemical/Metals,
http://linkedlifedata.com/resource/pubmed/chemical/Monophenol Monooxygenase,
http://linkedlifedata.com/resource/pubmed/chemical/Oxygen,
http://linkedlifedata.com/resource/pubmed/chemical/Peroxidase,
http://linkedlifedata.com/resource/pubmed/chemical/Superoxide Dismutase,
http://linkedlifedata.com/resource/pubmed/chemical/Superoxides
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jun
|
| pubmed:issn |
0022-2623
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
12
|
| pubmed:volume |
35
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
2261-74
|
| pubmed:dateRevised |
2007-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:1319496-5,7-Dihydroxytryptamine,
pubmed-meshheading:1319496-Animals,
pubmed-meshheading:1319496-Brain,
pubmed-meshheading:1319496-Catalase,
pubmed-meshheading:1319496-Ceruloplasmin,
pubmed-meshheading:1319496-Cytochrome c Group,
pubmed-meshheading:1319496-Electron Spin Resonance Spectroscopy,
pubmed-meshheading:1319496-Hydrogen Peroxide,
pubmed-meshheading:1319496-Hydrogen-Ion Concentration,
pubmed-meshheading:1319496-Hydroxides,
pubmed-meshheading:1319496-Hydroxyl Radical,
pubmed-meshheading:1319496-Metals,
pubmed-meshheading:1319496-Mitochondria,
pubmed-meshheading:1319496-Monophenol Monooxygenase,
pubmed-meshheading:1319496-Oxidation-Reduction,
pubmed-meshheading:1319496-Oxygen,
pubmed-meshheading:1319496-Oxygen Consumption,
pubmed-meshheading:1319496-Peroxidase,
pubmed-meshheading:1319496-Rats,
pubmed-meshheading:1319496-Superoxide Dismutase,
pubmed-meshheading:1319496-Superoxides
|
| pubmed:year |
1992
|
| pubmed:articleTitle |
Chemical and enzyme-mediated oxidation of the serotonergic neurotoxin 5,7-dihydroxytryptamine: mechanistic insights.
|
| pubmed:affiliation |
Department of Chemistry and Biochemistry, University of Oklahoma, Norman 73019.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
|