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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1979-9-17
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pubmed:abstractText |
Erythrocyte membranes prepared by three different procedures showed (Mg2+ + Ca2+)-ATPase activities differing in specific activity and in affinity for Ca2+. The (Mg2+ + Ca2+)-ATPase activity of the three preparations was stimulated to different extents by a Ca2+-dependent protein activator isolated from hemolysates. The Ca2+ affinity of the two most active preparations was decreased as the ATP concentration in the assay medium was increased. Lowering the ATP concentration from 2 mM to 2-200 microM or lowering the Mg:ATP ratio to less than one shifted the (Mg2+ + Ca2+)-ATPase activity in stepwise hemolysis membranes from mixed "high" and "low" affinity to a single high Ca2+ affinity. Membranes from which soluble proteins were extracted by EDTA (0.1 mM) in low ionic strength, or membranes prepared by the EDTA (1-10 mM) procedure, did not undergo the shift in the Ca2+ affinity with changes in ATP and MgCl2 concentrations. The EDTA-wash membranes were only weakly activated by the protein activator. It is suggested that the differences in properties of the (Mg2+ + Ca2+)-ATPase prepared by these three procedures reflect differences determined in part by the degree of association of the membrane with a soluble protein activator and changes in the state of the enzyme to a less activatable form.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphatases,
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Blood Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Magnesium
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pubmed:status |
MEDLINE
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pubmed:issn |
0091-7419
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
10
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
215-25
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:156819-Adenosine Triphosphatases,
pubmed-meshheading:156819-Adenosine Triphosphate,
pubmed-meshheading:156819-Blood Proteins,
pubmed-meshheading:156819-Calcium,
pubmed-meshheading:156819-Enzyme Activation,
pubmed-meshheading:156819-Erythrocyte Membrane,
pubmed-meshheading:156819-Erythrocytes,
pubmed-meshheading:156819-Humans,
pubmed-meshheading:156819-Kinetics,
pubmed-meshheading:156819-Magnesium
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pubmed:year |
1979
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pubmed:articleTitle |
Properties of (Mg2 + Ca2+)-ATPase of erythrocyte membranes prepared by different procedures: influence of Mg2+, Ca2+, ATP, and protein activator.
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pubmed:publicationType |
Journal Article
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