TY - JOUR
T1 - A model for cation adsorption in closed systems
T2 - Application to calcium binding to phospholipid vesicles
AU - Nir, Shlomo
PY - 1984/12
Y1 - 1984/12
N2 - A model for cation adsorption to negatively charged surfaces is developed and applied to the analysis of recent results on Ca2+ binding to phosphadidylserine (PS), phosphadylcholine (PC)/PS, and phosphatidylethanolamine (PE)/PS vesicles. The model combines electrostatics with specific binding and considers explicitly cation depletion from solution due to adsorption. Effect of concentration of surface sites on cation adsorption is elucidated for various combinations of cation concentrations and binding coefficients. Binding of Ca2+ to PS in pure and mixed vesicles which are intact and disperse is well accounted for by employing intrinsic binding coefficients whose values are KCa = 30 M-1, KNa = 0.8 M-1, and KMg = 20 M-1. Vesicles undergoing aggregation and fusion exhibit enhanced affinity of binding of Ca2+ to PS. It is proposed that the enhanced binding is associated with vesicle fusion.
AB - A model for cation adsorption to negatively charged surfaces is developed and applied to the analysis of recent results on Ca2+ binding to phosphadidylserine (PS), phosphadylcholine (PC)/PS, and phosphatidylethanolamine (PE)/PS vesicles. The model combines electrostatics with specific binding and considers explicitly cation depletion from solution due to adsorption. Effect of concentration of surface sites on cation adsorption is elucidated for various combinations of cation concentrations and binding coefficients. Binding of Ca2+ to PS in pure and mixed vesicles which are intact and disperse is well accounted for by employing intrinsic binding coefficients whose values are KCa = 30 M-1, KNa = 0.8 M-1, and KMg = 20 M-1. Vesicles undergoing aggregation and fusion exhibit enhanced affinity of binding of Ca2+ to PS. It is proposed that the enhanced binding is associated with vesicle fusion.
UR - http://www.scopus.com/inward/record.url?scp=0021624850&partnerID=8YFLogxK
U2 - 10.1016/0021-9797(84)90231-5
DO - 10.1016/0021-9797(84)90231-5
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AN - SCOPUS:0021624850
SN - 0021-9797
VL - 102
SP - 313
EP - 321
JO - Journal of Colloid and Interface Science
JF - Journal of Colloid and Interface Science
IS - 2
ER -