Linked Life Data

15362863

Source:http://linkedlifedata.com/resource/pubmed/id/15362863

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
37
pubmed:dateCreated
2004-9-14
pubmed:abstractText
Kinetic data have been collected suggesting a preferred sequential ordered kinetic mechanism for the histidine-tagged homocitrate synthase (HCS) from Saccharomyces cerevisiae with alpha-ketoglutarate binding before AcCoA and CoA released before homocitrate. Oxaloacetate is also a substrate for HCS, but with lower affinity than alpha-ketoglutarate. In agreement with the ordered kinetic mechanism desulfo-CoA is uncompetitive and citrate is competitive vs alpha-ketoglutarate. Varying AcCoA, citrate is a noncompetitive inhibitor as predicted, but CoA is noncompetitive vs AcCoA suggesting binding of CoA to E:homocitrate and E:alpha-ketoglutarate. The product CoA behaves in a manner identical to the dead-end analogue desulfo-CoA, suggesting an E:alpha-ketoglutarate:CoA dead-end complex. Data further suggest an irreversible reaction overall, in agreement with the downhill nature of the reaction as a result of homocitryl-CoA hydrolysis. Fluorescence titration data generally agree with the steady state data, but show finite binding of CoA and AcCoA to free enzyme, suggesting that the mechanism may be random with a high degree of synergism of binding between the reactants.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11790-5
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Kinetic mechanism of histidine-tagged homocitrate synthase from Saccharomyces cerevisiae.
pubmed:affiliation
Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, Oklahoma 73019, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't