Linked Life Data

21504201

Source:http://linkedlifedata.com/resource/pubmed/id/21504201

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2011-5-4
pubmed:abstractText
The isochorismate-pyruvate lyase from Pseudomonas aeruginosa (PchB) catalyzes two pericyclic reactions, demonstrating the eponymous activity and also chorismate mutase activity. The thermodynamic parameters for these enzyme-catalyzed activities, as well as the uncatalyzed isochorismate decomposition, are reported from temperature dependence of k(cat) and k(uncat) data. The entropic effects do not contribute to enzyme catalysis as expected from previously reported chorismate mutase data. Indeed, an entropic penalty for the enzyme-catalyzed mutase reaction (?S(++) = -12.1 ± 0.6 cal/(mol K)) is comparable to that of the previously reported uncatalyzed reaction, whereas that of the enzyme-catalyzed lyase reaction (?S(++) = -24.3 ± 0.2 cal/(mol K)) is larger than that of the uncatalyzed lyase reaction (-15.77 ± 0.02 cal/(mol K)) documented here. With the assumption that chemistry is rate-limiting, we propose that a reactive substrate conformation is formed upon loop closure of the active site and that ordering of the loop contributes to the entropic penalty for converting the enzyme substrate complex to the transition state.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1520-5126
pubmed:author
pubmed:copyrightInfo
© 2011 American Chemical Society
pubmed:issnType
Electronic
pubmed:day
11
pubmed:volume
133
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7229-33
pubmed:dateRevised
2011-9-26
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Entropic and enthalpic components of catalysis in the mutase and lyase activities of Pseudomonas aeruginosa PchB.
pubmed:affiliation
Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural