Linked Life Data

6433901

Source:http://linkedlifedata.com/resource/pubmed/id/6433901

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1984-10-24
pubmed:abstractText
By using density-gradient fractionation and high-voltage free-flow electrophoresis, human platelet membranes were separated into highly purified subfractions of surface (SM) and intracellular (IM) origin. Associated exclusively with the IM fraction is an ATP-dependent Ca2+ uptake that, in the absence of oxalate, reaches steady-state levels in 5-10 min. When Ca2+-EGTA buffers were used to control the external Ca2+ concentrations (range 0.1-50 microM) there was an increase in the intravesicle steady-state level of Ca2+ up to 10 microM external Ca2+ concentration. Above this level the intravesicle space becomes saturated at a concentration between 10 and 20 nmol of Ca2+ X (mg of protein)-1. The ionophore A23187 promotes a rapid and almost total release of the sequestered Ca2+ (greater than 90%, t1/2 1-2 min). The presence of oxalate in the external medium greatly enhances the Ca2+ accumulation to levels as high as 200 nmol X (mg of protein)-1, but the uptake process is more variable and rarely reaches steady-state level even after 2 h incubation. Moreover, accumulation in the presence of oxalate effects ionophore release with less than 80% depletion in 45-60 min. These findings, taken together with the known presence in the platelet of a wide variety of functional and metabolic processes triggered by this cation, suggest that the platelet IM has a key role in controlling cytosolic Ca2+ concentrations.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0264-6021
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
222
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
413-7
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Characterization of the calcium-sequestering process associated with human platelet intracellular membranes isolated by free-flow electrophoresis.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't