Linked Life Data

12859201

Source:http://linkedlifedata.com/resource/pubmed/id/12859201

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
28
pubmed:dateCreated
2003-7-15
pubmed:abstractText
The effects of phospholipid acyl chain length (n(c)) and cholesterol on several partial reactions of Na,K-ATPase reconstituted into liposomes of defined lipid composition are described. This regards the E(1)/E(2) equilibrium, the phosphoenzyme level, and the K(+)-deocclusion reaction. In addition, the lipid effects on some steady-state properties were investigated. Finally, the effects of cholesterol on the temperature sensitivity of the phosphorylation and spontaneous dephosphorylation reactions were investigated. The fatty acid and cholesterol composition of the native Na,K-ATPase membrane preparation showed a remarkable similarity to the lipid composition known to support maximum hydrolytic capacity as determined from in vitro experiments. The main rate-determining step of the Na,K-ATPase reaction, the E(2) --> E(1) reaction, as well as several other partial reactions were accelerated by cholesterol. This regards the phosphorylation by ATP as well as the E(1) - P --> E(2)-P reaction. Moreover, cholesterol shifted the E(1)/E(2) equilibrium toward the E(1) conformation and increased the K(+)-deocclusion rate. Finally, cholesterol significantly affected the temperature sensitivity of the spontaneous dephosphorylation reaction and the phosphorylation by ATP. The effects of cholesterol were not completely equivalent to those induced by increasing the phospholipid acyl chain length, indicating that the cholesterol effects are not entirely caused by increasing the hydrophobic bilayer thickness, which indicates an additional mechanism of action on the Na,K-ATPase.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8541-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Modulation of Na,K-ATPase by phospholipids and cholesterol. II. Steady-state and presteady-state kinetics.
pubmed:affiliation
Department of Biophysics, University of Aarhus, Ole Worms Allé 185, DK-8000, Denmark. fc@biophys.au.dk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't