Linked Life Data

2118386

Source:http://linkedlifedata.com/resource/pubmed/id/2118386

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-10-11
pubmed:abstractText
It was found that when Escherichia coli is grown in the presence of 0.2-0.3 mM menadione (2-methyl-1,4-naphthoquinone), an FMN-dependent NADH-quinone reductase increases more than 20-fold in the cytoplasmic fraction. The menadione-induced quinone reductase was isolated from the cytoplasmic fraction of induced cells. The purified enzyme had an Mr of 24 kDa on SDS-polyacrylamide gel electrophoresis. The enzyme required flavin as a cofactor and a half-maximum activity was obtained with 0.54 microM FMN or 16.5 microM FAD. The enzyme had a broad pH optimum at pH 7.0-8.0 and reacted with NADH, but not with NADPH. The reaction followed a ping-pong mechanism and the intrinsic Km values for NADH and menadione were estimated to be 132 microM and 2.0 microM, respectively. Dicoumarol was a simple competitive inhibitor with respect to NADH with a Ki value of 0.22 microM. The electron acceptor specificity of this enzyme was very similar to that of NAD(P)H: (quinone acceptor) oxidoreductase (EC 1.6.99.2, DT-diaphorase) from rat liver. Since menadione is reduced by the two-electron reduction pathway to menadiol, the induction of this enzyme is likely to be an adaptive response of E. coli to partially alleviate the toxicity of menadione.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
1035
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
230-6
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Characterization of FMN-dependent NADH-quinone reductase induced by menadione in Escherichia coli.
pubmed:affiliation
Laboratory of Membrane Biochemistry, Faculty of Pharmaceutical Sciences, Chiba University, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't