Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1985-3-29
pubmed:abstractText
Effects of various calmodulin antagonists and calmodulin on the incorporation of serine, ethanolamine and choline into the corresponding phospholipids, such as phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine by Ca2+-stimulated base-exchange reactions in rabbit platelet membranes were studied. Under a Ca2+-EGTA buffer system, the incorporation of three bases were stimulated by Ca2+ in a biphasic manner. Minimum requirement of free Ca2+ for the reactions was found to be around 0.5 microM and maximal incorporation took place at high Ca2+ concentrations (3-5 mM). Various calmodulin antagonists such as chlorpromazine, trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, not only activated the three reactions but also greatly enhanced their sensitivity to Ca2+ (K0.5, 0.1-0.3 microM). In the absence of Ca2+, however, the drugs did not show any effect on the reactions. The concentrations of the drugs required for half maximal stimulation were approx. 30-40 microM. Although platelet membranes contained endogenous calmodulin (0.3-0.6 microgram/mg of membrane protein), the addition of exogenous calmodulin inhibited choline exchange activity but had no or little effect on serine or ethanolamine exchange activity. The results suggest that in the presence of low Ca2+ concentrations, these drugs markedly stimulate base-exchange activities, and choline exchange activity may be regulated by calmodulin.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0049-3848
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
267-78
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Effects of calmodulin antagonists and calmodulin on phospholipid base-exchange activities in rabbit platelets.
pubmed:publicationType
Journal Article, In Vitro