Linked Life Data

11732922

Source:http://linkedlifedata.com/resource/pubmed/id/11732922

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
49
pubmed:dateCreated
2001-12-4
pubmed:abstractText
ATP sulfurylase, from Escherichia coli Kappa-12, is a GTPase target complex that catalyzes and couples the chemical potentials of two reactions: GTP hydrolysis and activated sulfate (APS) synthesis. Previous work suggested that the product release branch of the GTPase mechanism might include rate-determining release and/or isomerization step(s). Such steps are known to couple chemical potentials in other energy transducing systems. Rate-determining, product release step(s) were confirmed in the ATP sulfurylase-GTPase reaction by a burst of product in pre-steady-state, rapid-quench experiments. Classical rapid-quench experiments, which measure total product formation, do not allow the slow steps to be assigned to the release of a specific product, or to slow isomerization, because they do not distinguish solution-phase from enzyme-bound product. Assay systems that exclusively monitor solution-phase P(i) and GDP were used to obtain free product progress curves during the first turnover of ATP sulfurylase. Together, the free and total product data describe how the products partition between the enzyme surface and solution during the first turnover. In combination, the data provide the time dependence of the concentrations of specific product intermediates, AMP.PP(i).E.GDP.P(i) and AMP.PP(i).E.GDP, the rate constants for the release of P(i) (4.2 s(-1)) and GDP (4.8 s(-1)) from these complexes, respectively, and the equilibrium constant for the enzyme-bound, beta,gamma-bond cleavage reaction: [AMP.PP(i).E.GTP']/[AMP.PP(i).E.GDP.P(i)] = 0.7. The data are fit, using global analysis, to obtain a complete kinetic and energetic description of this GTPase reaction.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15009-16
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Product release during the first turnover of the ATP sulfurylase-GTPase.
pubmed:affiliation
The Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461-1926, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.