Linked Life Data

8631749

Source:http://linkedlifedata.com/resource/pubmed/id/8631749

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
1996-7-3
pubmed:abstractText
Inducible nitric oxide (NO) synthase (iNOS) is comprised of an oxygenase domain containing heme, tetrahydrobiopterin, the substrate binding site, and a reductase domain containing FAD, FMN, calmodulin, and the NADPH binding site. Enzyme activity requires a dimeric interaction between two oxygenase domains with the reductase domains attached as monomeric extensions. To understand how dimerization activates iNOS, we synthesized an iNOS heterodimer comprised of one full-length subunit and one histidine-tagged subunit that was missing its reductase domain. The heterodimer was purified using nickel-Sepharose and 2',5'-ADP affinity chromatography. The heterodimer catalyzed NADPH-dependent NO synthesis from L-arginine at a rate of 52 +/- 6 nmol of NO/min/nmol of heme, which is half the rate of purified iNOS homodimer. Heterodimer NO synthesis was associated with reduction of only half of its heme iron by NADPH, in contrast with near complete heme iron reduction in an iNOS homodimer. Full-length iNOS monomer preparations could not synthesize NO nor catalyze NADPH-dependent heme iron reduction. Thus, dimerization activates NO synthesis by enabling electrons to transfer between the reductase and oxygenase domains. Although a single reductase domain can reduce only one of two hemes in a dimer, this supports NO synthesis from L-arginine.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7309-12
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Heme iron reduction and catalysis by a nitric oxide synthase heterodimer containing one reductase and two oxygenase domains.
pubmed:affiliation
Department of Immunology, Cleveland Clinic Research Institute, Ohio 44195, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't