Linked Life Data

12488013

Source:http://linkedlifedata.com/resource/pubmed/id/12488013

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2002-12-18
pubmed:abstractText
The animal and human pathogen Listeria monocytogenes secretes several virulence factors, including a phosphatidylinositol-specific phospholipase C (PI-PLC). Sufficient quantities of L. monocytogenes PI-PLC for biophysical studies were obtained by overexpression of the enzyme in Escherichia coli. The purified PI-PLC was examined in enzyme kinetics experiments using a new fluorogenic substrate, methyl-FLIP. Methyl-FLIP is a water-soluble monomeric substrate cleaved in a manner similar to the natural aggregate substrate, phosphatidylinositol (PI). Michaelis-Menten kinetics were observed with K(M) = 61 +/- 7 microM and V(max) = 120 +/- 5 micromol min(-1) mg(-1), corresponding to k(cat) = 66+/-3 s(-1). The catalysis is activated by the addition of a short-chain phospholipid, dihexanoyl phosphatidylcholine (diC(6)PC). The kinetics were fitted to a two-site model in which the substrate binds to the active site and diC(6)PC binds to a second site, with an interaction between the two sites. The result is a decrease in K(M) and an increase in V(max), producing an overall four to five-fold increase in catalytic efficiency (k(cat)/K(M)). The interaction is not a regulatory mechanism, as is the case for multimeric enzymes; rather, it suggests interfacial cooperativity between the active site and a lipid-binding subsite, presumably adjacent to the active site.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0301-4622
pubmed:author
pubmed:copyrightInfo
Copyright 2002 Elsevier Science B.V.
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
101-102
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
347-58
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Listeria monocytogenes phosphatidylinositol-specific phospholipase C: activation and allostery.
pubmed:affiliation
Institute of Molecular Biology, University of Oregon, Eugene, OR 97403-1253, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.