Linked Life Data

7947799

Source:http://linkedlifedata.com/resource/pubmed/id/7947799

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
46
pubmed:dateCreated
1994-12-21
pubmed:abstractText
We have studied the effects of cyclopiazonic acid (CPA) and halothane on the enzymatic activity, oligomeric state, and conformational equilibrium of the Ca-ATPase in skeletal muscle sarcoplasmic reticulum (SR). CPA is a potent inhibitor of Ca-ATPase activity, and this inhibition is competitive with respect to ATP concentration. Time-resolved phosphorescence anisotropy was used to detect the fraction of Ca-ATPase monomers, dimers, and larger aggregates in the absence and presence of CPA. CPA increased the fraction of dimers and larger aggregates of the Ca-ATPase. Addition of halothane to SR, or detergent solubilization of the Ca-ATPase, increased the apparent KI of CPA inhibition, and increased the fraction of Ca-ATPase present as monomers. CPA stabilized the E2 conformational state of the Ca-ATPase relative to the E1 and E2-P states, as measured by fluorescein 5-isothiocyanate fluorescence and enzyme phosphorylation from inorganic phosphate. E2-P formation in the presence of CPA was partially restored by halothane and solubilization. We conclude that CPA inhibits the Ca-ATPase in part by overstabilizing dimers or small oligomers of the Ca-ATPase, which is correlated with stabilization of the E2 conformation of the enzyme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
13928-37
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Halothane and cyclopiazonic acid modulate Ca-ATPase oligomeric state and function in sarcoplasmic reticulum.
pubmed:affiliation
Department of Biochemistry, University of Minnesota Medical School, Minneapolis 55455.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't