Linked Life Data

15909977

Source:http://linkedlifedata.com/resource/pubmed/id/15909977

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2005-5-24
pubmed:abstractText
3-Hydroxyanthranilate-3,4-dioxygenase (HAD) is a non-heme Fe(II) dependent enzyme that catalyzes the oxidative ring-opening of 3-hydroxyanthranilate to 2-amino-3-carboxymuconic semialdehyde. The enzymatic product subsequently cyclizes to quinolinate, an intermediate in the biosynthesis of nicotinamide adenine dinucleotide. Quinolinate has also been implicated in important neurological disorders. Here, we describe the mechanism by which 4-chloro-3-hydroxyanthranilate inhibits the HAD catalyzed reaction. Using overexpressed and purified bacterial HAD, we demonstrate that 4-chloro-3-hydroxyanthranilate functions as a mechanism-based inactivating agent. The inactivation results in the consumption of 2 +/- 0.8 equiv of oxygen and the production of superoxide. EPR analysis of the inactivation reaction demonstrated that the inhibitor stimulated the oxidation of the active site Fe(II) to the catalytically inactive Fe(III) oxidation state. The inactivated enzyme can be reactivated by treatment with DTT and Fe(II). High resolution ESI-FTMS analysis of the inactivated enzyme demonstrated that the inhibitor did not form an adduct with the enzyme and that four conserved cysteines were oxidized to two disulfides (Cys125-Cys128 and Cys162-Cys165) during the inactivation reaction. These results are consistent with a mechanism in which the enzyme, complexed to the inhibitor and O2, generates superoxide which subsequently dissociates, leaving the inhibitor and the oxidized iron center at the active site.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
31
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7623-31
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
The mechanism of inactivation of 3-hydroxyanthranilate-3,4-dioxygenase by 4-chloro-3-hydroxyanthranilate.
pubmed:affiliation
Department of Chemistry and Chemical Biology, 120 Baker Laboratory, Cornell University, Ithaca, New York 14853, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, N.I.H., Extramural