Source:http://linkedlifedata.com/resource/pubmed/id/14609342
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
45
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| pubmed:dateCreated |
2003-11-11
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| pubmed:abstractText |
Thioredoxin reductase (TrxR) is the homodimeric flavoenzyme that catalyzes reduction of thioredoxin disulfide (Trx). For Plasmodium falciparum, a causative agent of tropical malaria, TrxR is an essential protein which has been validated as a drug target. The high-throughput screening of 350000 compounds has identified Mannich bases as a new class of TrxR mechanism-based inhibitors. During catalysis, TrxR conducts reducing equivalents from the NADPH-reduced flavin to Trx via the two redox-active cysteine pairs, Cys88-Cys93 and Cys535'-Cys540', referred to as N-terminal and C-terminal cysteine pairs. The structures of unsaturated Mannich bases suggested that they could act as bisalkylating agents leading to a macrocycle that involves both C-terminal cysteines of TrxR. To confirm this hypothesis, different Mannich bases possessing one or two electrophilic centers were synthesized and first studied in detail using glutathione as a model thiol. Michael addition of glutathione to the double bond of an unsaturated Mannich base (3a) occurs readily at physiological pH. Elimination of the amino group, promoted by base-catalyzed enolization of the ketone, is followed by addition of a second nucleophile. The intermediate formed in this reaction is an alpha,beta-unsaturated ketone that can react rapidly with a second thiol. When studying TrxR as a target of Mannich bases, we took advantage of the fact that the charge-transfer complex formed between the thiolate of Cys88 and the flavin in the reduced enzyme can be observed spectroscopically. The data show that it is the C-terminal Cys 535'-Cys540' pair rather than the N-terminal Cys88-Cys93 pair that is modified by the inhibitor. Although alkylated TrxR is unable to turn over its natural substrate Trx, it can reduce low M(r) electron acceptors such as methyl methanethiolsulfonate by using its unmodified N-terminal thiols. On the basis of results with chemically distinct Mannich bases, a detailed mechanism for the inactivation of TrxR is proposed.
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| pubmed:grant | |
| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Alkylating Agents,
http://linkedlifedata.com/resource/pubmed/chemical/Dithionitrobenzoic Acid,
http://linkedlifedata.com/resource/pubmed/chemical/Enzyme Inhibitors,
http://linkedlifedata.com/resource/pubmed/chemical/Glutathione,
http://linkedlifedata.com/resource/pubmed/chemical/Glutathione Reductase,
http://linkedlifedata.com/resource/pubmed/chemical/Mannich Bases,
http://linkedlifedata.com/resource/pubmed/chemical/Methyl Methanesulfonate,
http://linkedlifedata.com/resource/pubmed/chemical/NADP,
http://linkedlifedata.com/resource/pubmed/chemical/Propiophenones,
http://linkedlifedata.com/resource/pubmed/chemical/Thioredoxin-Disulfide Reductase,
http://linkedlifedata.com/resource/pubmed/chemical/U 0882,
http://linkedlifedata.com/resource/pubmed/chemical/methyl methanethiosulfonate
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| pubmed:status |
MEDLINE
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| pubmed:month |
Nov
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| pubmed:issn |
0006-2960
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| pubmed:author |
pubmed-author:AndricopuloAdriano DAD,
pubmed-author:ArscottL DavidLD,
pubmed-author:BeckerKatjaK,
pubmed-author:Davioud-CharvetElisabethE,
pubmed-author:GiegelDavidD,
pubmed-author:KenyonGeorge LGL,
pubmed-author:MüllerSylkeS,
pubmed-author:McLeishMichael JMJ,
pubmed-author:SchirmerR HeinerRH,
pubmed-author:VeineDonna MDM,
pubmed-author:WilliamsCharles HCHJr
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| pubmed:issnType |
Print
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| pubmed:day |
18
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| pubmed:volume |
42
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
13319-30
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| pubmed:dateRevised |
2007-11-15
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| pubmed:meshHeading |
pubmed-meshheading:14609342-Alkylating Agents,
pubmed-meshheading:14609342-Animals,
pubmed-meshheading:14609342-Dithionitrobenzoic Acid,
pubmed-meshheading:14609342-Dose-Response Relationship, Drug,
pubmed-meshheading:14609342-Enzyme Inhibitors,
pubmed-meshheading:14609342-Glutathione,
pubmed-meshheading:14609342-Glutathione Reductase,
pubmed-meshheading:14609342-Humans,
pubmed-meshheading:14609342-Hydrogen-Ion Concentration,
pubmed-meshheading:14609342-Kinetics,
pubmed-meshheading:14609342-Mannich Bases,
pubmed-meshheading:14609342-Methyl Methanesulfonate,
pubmed-meshheading:14609342-Models, Chemical,
pubmed-meshheading:14609342-NADP,
pubmed-meshheading:14609342-Oxidation-Reduction,
pubmed-meshheading:14609342-Plasmodium falciparum,
pubmed-meshheading:14609342-Propiophenones,
pubmed-meshheading:14609342-Thioredoxin-Disulfide Reductase
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| pubmed:year |
2003
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| pubmed:articleTitle |
Mechanism-based inactivation of thioredoxin reductase from Plasmodium falciparum by Mannich bases. Implication for cytotoxicity.
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| pubmed:affiliation |
College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109-1065, USA.
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| pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't
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