Linked Life Data

8573583

Source:http://linkedlifedata.com/resource/pubmed/id/8573583

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1996-3-13
pubmed:abstractText
The active metabolite of leflunomide. A771726, is a novel immunosuppressive compound that has been shown to be a powerful antiproliferative agent for mononuclear and T-cells. The molecular mechanism of action for this compound has not been clearly established. In vitro cellular and enzymatic assays, however, demonstrate that leflunomide is an inhibitor of several protein tyrosine kinases, with IC50 values between 30 and 100 microM. The in vivo properties of A771726 are reminiscent of another immunosuppressive agent, brequinar sodium, which has been shown to be a nonomolar inhibitor (Ki = 10-30 nM) of the enzyme dihydroorotate dehydrogenase (DHODase). On the basis, we have investigated the effects of leflunomide and A771726 on the activity of purified recombinant human DHODase. We find that A771726 is a potent inhibitor of DHODase (Ki = 179 +/- 19 nM), while the parent compound, leflunomide, had no inhibitory effect at concentrations as high as 1 microM. Studies of the dependence of inhibition on the concentrations of the substrates ubiquinone and dihydroorotate demonstrate that A771726 is a competitive inhibitor of the ubiquinone binding site and is noncompetitive with respect to dihydroorotate. The potency of A771726 as a DHODase inhibitor is thus 100-100-fold greater than that reported for its inhibition of protein tyrosine kinases. These data suggest that an alternative explanation for the immunosuppressive efficacy of A771726 may be the potent inhibition of DHODase by this compound.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1270-3
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
The immunosuppressive metabolite of leflunomide is a potent inhibitor of human dihydroorotate dehydrogenase.
pubmed:affiliation
Inflammatory Diseases Research and Chemical and Physical Sciences, DuPont Merck Research Laboratories, Wilmington, Delaware 19880-0400, USA.
pubmed:publicationType
Journal Article, Comparative Study