Linked Life Data

6467080

Source:http://linkedlifedata.com/resource/pubmed/id/6467080

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1984-10-11
pubmed:abstractText
Calcium binding to leaky erythrocyte plasma membranes was measured by three different procedures: Millipore filtration, equilibrium dialysis, and partition centrifugation. The curve derived from the binding equation, which best fit the means of the raw data, was used to estimate the association constants and capacities of the binding sites. A computer program (Gaushaus) which uses a nonlinear, least-squares regression protocol was also used to confirm these estimates. On the basis of these analyses we propose the presence of three classes of calcium-binding sites with the following apparent association constants and capacities: site 1, Ka = 3 X 10(4) M-1 and n = 30 nmol/mg protein; site 2, Ka = 3 X 10(3) M-1 and n = 200 nmol/mg protein; site 3, Ka = approximately 10(2) M-1 and n = approximately 200 nmol/mg protein. Calcium binding to erythrocyte membranes sealed in a high-salt solution showed the presence of site 3, but not site 2. The influence of phospholipids on the binding of calcium was evaluated by pretreating ghosts with phospholipase C (Clostridium welchii, EC 3.1.4.3). Treatment with this enzyme removed 80% of the total membrane phosphorus, predominantly from sphingomyelin, phosphatidylcholine, and phosphatidylethanolamine. By the method of partition centrifugation two classes of binding sites were identified by computer analysis. Their association constants and capacities are, respectively, 1.1 X 10(5) M-1 and 20 nmol/mg protein for site 1 and 4.4 X 10(3) M-1 and 200 nmol/mg protein for site 2. We speculate that calcium-binding site 1 is composed of acidic phospholipids, calcium-binding site 2 is composed of spectrin and actin, and calcium-binding site 3 is composed of sialic acid.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0714-7511
pubmed:author
pubmed:issnType
Print
pubmed:volume
62
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
398-408
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
The determination of calcium-binding sites of human erythrocyte membranes.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't