Ca binding to the human red cell membrane: Characterization of membrane preparations and binding sites

Solomon, A. K.; Cohen, Carl M.

doi:10.1007/bf01868970

Cited by 40 publications

(16 citation statements)

References 45 publications

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“…Under our experimental conditions and in agreement with previous observations, 15 calcium binding to erythrocyte membranes reached the equilibrium within 1 minute at 25° C, and it remained constant up to 60 minutes at both calcium concentrations used in the study. The binding to erythrocyte ghosts was rapidly (3 minutes) reversible by lowering the free calcium concentration with the addition of an excess of EGTA, but it was not affected by the calcium ionophore A 23187 (1 (imoVl).…”

Section: Resultssupporting

confidence: 79%

Calcium binding capacity of erythrocyte membrane in human hypertension.

1989

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The cell membrane calcium binding capacity of genetically hypertensive rats is reduced when measured in the presence of the submicromolar calcium concentrations proper of intracellular environment. The present work, performed as an ancillary study to an epidemiological survey on an entire population, aimed to investigate the existence of a similar abnormality in human hypertension. Calcium binding to the erythrocyte membrane was measured in clinically healthy normotensive (n=12) and hypertensive individuals (n=24). For this purpose, a nitration technique was used, based on the determination of "Ca bound to the erythrocyte membrane in the presence of free calcium concentrations ( 1 Previous studies have reported altered calcium metabolism in both rat and human arterial hypertension.2 -3 In genetically hypertensive rats it has been reported that, in addition to abnormalities of extracellular calcium homeostasis, the membrane calcium binding capacity in the presence of calcium concentra-

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Section: Resultssupporting

confidence: 79%

Calcium binding capacity of erythrocyte membrane in human hypertension.

1989

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“…Of the divalent cations examined in this study the association of calcium with the erythrocyte membrane has received the greatest amount of attention. Sialic acid residues on the erythrocyte glycoproteins form a major portion of the calcium-binding sites on the outer cell face, although as much as 30% of the binding sites may be independent of the sialic acid residues (Cohen and Solomon, 1976;Long and Mouat, 1971).…”

Section: Neuraminidasementioning

confidence: 99%

“…Two of the binding sites are susceptible to neuraminidase treatment (Cohen and Solomon, 1976) and may represent sites of differing accessibility to the neuraminidase.…”

Section: Neuraminidasementioning

confidence: 99%

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Divalent cation effects on membrane bending in heated erythrocytes

Coakley

Doulah

1984

J Biol Phys

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ABSTRACT:The thermal fragmentation of human erythroeytes involves either surface wave growth and membrane externalization at the cell rim or membrane internalization at the cell dimple.In symmetrical monovalent electrolytes an increase in membrane internalization at the cell dimple correlates with the decrease in zeta potential arising from surface charge (sialic acid residue) depletion.The influence of divalent cations on thermal fragmentation is examined in this work.The erythrocyte zeta potential decreased when divalent cations replaced some Na + in the cell-suspending phase.The incidence of membrane internalization increased in rank order Ca 2+ > Ba 2+ > Mg ~+ ~ Sr 2+. Calcium continued to influence the thermal fragmentation of cells highly depleted of sialic acid, suggesting that the ion also interacted with membrane sites other than sialic acid.The divalent cation influence on cell fragmentation was shown to be greater than that due to zeta potential decrease alone.This conclusion was supported by the observation that the divalent cation-induced changes in zeta potential showed much less cation specificity than did the changes induced in the thermal fragmentation pattern. The result implies that the specificity of the divalent cation effects was due to interactions within the erythrocyte shear layer.The possibility that the interaction is with membrane lipids is examined.

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“…These findings indicate that the Ca concentrations in solutions nominally free of Ca, ranging between 0.2 and 10/XM, may cause a substantial contamination of the intracellular Ca by extracellular Ca. At a Ca concentration of 10/XM, for instance, the external high-affinity Ca binding sites (exhibiting binding constants of 6 x 104 [27] to 1.6 x 106 liter/mole [5]) would be saturated with Ca by 40 to 96%. If the capacity of these binding sites is taken to be 16/zmol/liter cells [27], about 6.4 to 15.4 /xmol Ca/liter cells would be bound to the outer aspect of the membrane at 10/XM Ca in the medium.…”

Section: Introductionmentioning

confidence: 99%

Intracellular calcium content of human erythrocytes: Relation to sodium transport systems

Engelmann

Duhm

1987

J. Membrain Biol.

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To study the possible role of intracellular Ca (Cai) in controlling the activities of the Na+-K+ pump, the Na+-K+ cotransport and the Na+/Li+ exchange system of human erythrocytes, a method was developed to measure the amount of Ca embodied within the red cell. For complete removal of Ca associated with the outer aspect of the membrane, it proved to be essential to wash the cells in buffers containing less than 20 nM Ca. Ca was extracted by HClO4 in Teflon vessels boiled in acid to avoid Ca contaminations and quantitated by flameless atomic absorption. Cai of fresh human erythrocytes of apparently healthy donors ranged between 0.9 and 2.8 mumol/liter cells. The mean value found in females was significantly higher than in males. The interindividual different Ca contents remained constant over periods of more than one year. Sixty to 90% of Cai could be removed by incubation of the cells with A23187 and EGTA. The activities of the Na+-K+ pump, of Na+-K+ cotransport and Na+/Li+ exchange and the mean cellular hemoglobin content fell with rising Cai; the red cell Na+ and K+ contents rose with Cai. Ca depletion by A23187 plus EGTA as well as chelation of intracellular Ca2+ by quin-2 did not significantly enhance the transport rates. It is concluded that the large scatter of the values of Cai of normal human erythrocytes reported in the literature mainly results from a widely differing removal of Ca associated with the outer aspect of the membrane.

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Ca binding to the human red cell membrane: Characterization of membrane preparations and binding sites

Cited by 40 publications

References 45 publications

Calcium binding capacity of erythrocyte membrane in human hypertension.

Calcium binding capacity of erythrocyte membrane in human hypertension.

Divalent cation effects on membrane bending in heated erythrocytes

Intracellular calcium content of human erythrocytes: Relation to sodium transport systems

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