Adsorption of polyvalent cations to bilayer membranes from negatively charged lipid: estimating the lipid accessibility in the case of complete bindingстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:The effect of trivalent (Gd3+ and Yb3+) and divalent (Be2+ and Ca2+) cations on suspensions of multilamellar liposomes formed from brain PS and DMPS has been studied using microelectrophoresis and DSC techniques, respectively. The zeta potential values have been shown to strongly depend on the total lipid concentration in the suspension. At moderate concentrations of the polyvalent cations, the total cation concentration exceeds the bulk one several times due to adsorption of cations to the liposomes. A modification of the Gouy-Chapman-Stern theory in the case of unknown bulk concentration of the polyvalent cation is presented. An intrinsic association constant for Be2+ ions was evaluated to be about K-2 similar to 50 M-1. The algorithm for estimating the concentrations of the accessible (to exogenously added polyvalent cations) lipid-binding sites is described. These values are consistent with the subsurface concentrations' of the polyvalent cations. which monotonously increase with the total concentration of the polyvalent cations. The calculated lipid accessibilities are shown to be in accordance with the DSC data. (C) 2000 Elsevier Science B.V. All rights reserved.