Cation Binding to Brain Plasma Membranes. An Evaluation of the Use of Anionic Fluorescent Probes

Krishnan, KS and Balaram, P (1976) Cation Binding to Brain Plasma Membranes. An Evaluation of the Use of Anionic Fluorescent Probes. In: Archives of Biochemistry and Biophysics, 174 . pp. 420-430.

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Abstract

Cation binding to brain plasma membranes has been studied using anionic sulfonate fluorescent probes. Ion affinity sequences follow the order Mg2+ > Ca2+ > K+ > Cs+ > Na+ > Li+. The order of effectiveness, in increasing probe fluorescence, is the reverse of the affinity sequence for ions of the same charge. The affinity orders for erythrocyte membranes and dipalmitoyl lecithin are Mg2+ > Ca2+ > K+ > Na+ > Li+ and Mg2+ > Ca2+ > Li+ > Na+ > K+ > Cs+. These sequence variations are related to the differences in the nature of ion binding sites. Heterogeneity in ion binding sites is demonstrated. Evidence is presented for the role of proteins in binding hydrophobic probes. The problem of separating specific conformational effects of ion binding from nonspecific charge neutralization effects is discussed. Pyrene excimer fluorescence rules out the possibility of extensive changes in mobility in the lipid phase on cation binding. Tetrodotoxin has been shown to inhibit Li+-, Na+ - and K+ - induced fluorescence enhancements of 1-aniline-8-napthalene sulfonate bound to brain membranes.

Item Type:	Journal Article
Publication:	Archives of Biochemistry and Biophysics
Publisher:	Academic Press
Additional Information:	Copyright for this article belongs to Academic Press
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	26 Jul 2004
Last Modified:	19 Sep 2010 04:14
URI:	http://eprints.iisc.ac.in/id/eprint/1157

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