Linked Life Data

3117624

Source:http://linkedlifedata.com/resource/pubmed/id/3117624

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1987-12-16
pubmed:abstractText
DT-diaphorase catalyzes the two-electron reduction of the unsubstituted quinone epoxide, 2,3-epoxy-p-benzoquinone, at expense of NAD(P)H with formation of 2-OH-p-benzohydroquinone as the reaction product. The further conversion reactions of 2-OH-p-benzohydroquinone are influenced by the presence of O2 in the medium. Under aerobic conditions, 2-OH-p-benzohydroquinone undergoes autoxidation--probably with formation of 2-OH-semiquinone intermediates--to 2-OH-p-benzoquinone. The latter product is rapidly reduced by DT-diaphorase and, thus, its accumulation can be only observed upon exhaustion of NADPH. Under anaerobic conditions, 2-OH-p-benzohydroquinone does not undergo autoxidation and its accumulation is stoichiometrically (1:1) related to the amount of NADPH oxidized and epoxide substrate reduced. DT-diaphorase also catalyzes the reduction of the disubstituted quinone epoxide, 2,3-dimethyl-2,3-epoxy-1,4-naphthoquinone. Neither the aliphatic epoxide, trans-stilbene oxide, nor the aromatic epoxide, 4,5-epoxy-benzo[a]pyrene are substrates for DT-diaphorase. The reduction of 2,3-epoxy-p-benzoquinone is also catalyzed by the one-electron transfer enzyme, NADPH-cytochrome P450 reductase at a rate similar to that found with DT-diaphorase. However, this reaction differs from that catalyzed by DT-diaphorase in the distribution of molecular products as well as in the relative contribution of nonenzymatic reactions, i.e. semiquinone disproportionation and autoxidation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0891-5849
pubmed:author
pubmed:issnType
Print
pubmed:volume
3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
181-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
DT-diaphorase-catalyzed two-electron reduction of quinone epoxides.
pubmed:affiliation
Department of Pathology II, Linköping University, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't