Linked Life Data

3199593

Source:http://linkedlifedata.com/resource/pubmed/id/3199593

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1989-1-26
pubmed:abstractText
Liver microsomal vitamin K epoxide reductase activity was determined by measuring the formation of menaquinone-4 from the substrate menaquinone-4 2,3-epoxide. The enzyme was active when dithiothreitol (DTT) was used as a reducing agent, and the activity increased gradually with increasing concentrations of DTT. Glutathione and cysteine also functioned as reductants, but these physiological reductants showed less than 15% of the activity detected with 0.5 mM DTT. Addition of various beta-lactam antibiotics to the assay mixture for vitamin K epoxide reductase caused a slight inhibition of the activity. N-Methyltetrazolethiol (NMTT) and other heterocyclic thiol compounds also inhibited the enzyme activity in vitro depending on their concentrations. Most of these antibiotics and heterocyclic thiol compounds inhibited the enzyme activity only 10-25% in the in vitro assay system even when higher concentrations were added (5-10 mM). Among the compounds tested, methyl-thiadiazolethiol was the only compound that caused 50% inhibition of the enzyme activity. NMTT-induced inhibition was diminished gradually by increasing DTT concentrations. Kinetic analysis of the inhibitory action of heterocyclic thiol compounds showed competitive inhibition against the reductant DTT and non-competitive inhibition against the substrate. On the other hand, warfarin, a typical anticoagulant, showed different patterns in the inhibitory action: non-competitive inhibition against DTT and mixed-type inhibition against the substrate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-5198
pubmed:author
pubmed:issnType
Print
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
169-78
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
In vitro effect of beta-lactam antibiotics and N-methyltetrazolethiol on microsomal vitamin K epoxide reductase in rats.
pubmed:affiliation
Shionogi Research Laboratories, Shionogi & Co., Ltd., Osaka, Japan.
pubmed:publicationType
Journal Article, Comparative Study, In Vitro