Effect of the alkyl chain length of monocarboxylic acid on the permeation through bilayer lipid membranes

Veronika Yu Evtodienko, Olga N. Kovbasnjuk, Yuri N. Antonenko, Lev S. Yaguzhinsky

Research output: Contribution to journalArticlepeer-review

Abstract

Electrically silent hydrogen ion fluxes across a planar bilayer lipid membrane (BLM) induced by an addition of monocarboxylic acid at one side of BLM were studied by measuring pH changes in the unstirred layers near the BLM surface. The pH changes were assayed by recording protonophore-dependent potentials as well as by direct measurements of pH shifts in the unstirred layers close to the membrane by the pH microelectrode. It was shown that the mechanism of the acid transport changed qualitatively upon the increase of the hydrophobic chain length of the acid. In the case of short-chain acids at pH < pK(a), the total transport was limited by diffusion of the anionic form of the acid across the unstirred layers, while at the alkaline pH (pH > > pK(a)) the transport was limited by diffusion of the neutral form across the membrane. In the alkaline pH range the pH shifts induced by short-chain acids were sensitive to the presence of cholesterol in the BLM as well as to the stirring conditions in the cell. However, in the case of long chain acids (more than 8 carbonic atoms) the transport was limited by diffusion of the anionic form of the acid in the whole range of pH studied. In the latter case, pH changes in the unstirred layers did not depend on the presence of cholesterol in the membrane, and moreover pH shifts were not dependent on the thickness of the unstirred layer. It was proposed that the peculiarities of the long-chain acid-induced proton transport were associated with the formation of micelles of the acid in bathing solutions.

Original languageEnglish (US)
Pages (from-to)245-251
Number of pages7
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1281
Issue number2
DOIs
StatePublished - Jun 11 1996
Externally publishedYes

Keywords

  • Bilayer lipid membrane
  • Fatty acid
  • Monocarboxylic acid
  • Permeability
  • Unstirred layer

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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