TY - JOUR

T1 - Use of isothermal titration calorimetry to study the interaction of short-chain alcohols with lipid membranes

AU - Trandum, Christa

AU - Westh, Peter

AU - Jørgensen, Kent

AU - Mouritsen, Ole G.

PY - 1999/3/22

Y1 - 1999/3/22

N2 - The molecular mechanisms by which ethanol and other short-chain alcohols exert their effect in biological systems have been suggested to involve specific interactions with proteins and/or non-specific interactions with the lipid bilayer part of the cell membrane. To gain insight into the effect of short-chain alcohols on lipid bilayers, isothermal titration calorimetry (ITC) has been used to determine the energy involved in the association of the alcohols with lipid bilayers. Pure unilamellar DMPC liposomes and DMPC liposomes incorporated with different amounts of cholesterol, sphingomyelin and ganglioside (GM1) were investigated at temperatures above, and below, the main phase-transition temperature of DMPC. The alcohols used were ethanol, 1-propanol, and 1-butanol. The calorimetric results reveal that the interaction of short-chain alcohols with the lipid bilayer is endothermic and strongly dependent on the lipid bilayer composition. In the presence of high concentrations of cholesterol, the binding enthalpy of ethanol is decreased, whereas the presence of ceramides enhances the enthalpic response of the lipid bilayer to ethanol. Isothermal titration calorimetry offers a new methodology of investigating molecular interactions and for determining partitioning coefficients for alcohols into lipid bilayers. We have estimated the partitioning coefficients for the three alcohols between the aqueous phase and the lipid bilayers of various lipid composition on the basis of calorimetric results.

AB - The molecular mechanisms by which ethanol and other short-chain alcohols exert their effect in biological systems have been suggested to involve specific interactions with proteins and/or non-specific interactions with the lipid bilayer part of the cell membrane. To gain insight into the effect of short-chain alcohols on lipid bilayers, isothermal titration calorimetry (ITC) has been used to determine the energy involved in the association of the alcohols with lipid bilayers. Pure unilamellar DMPC liposomes and DMPC liposomes incorporated with different amounts of cholesterol, sphingomyelin and ganglioside (GM1) were investigated at temperatures above, and below, the main phase-transition temperature of DMPC. The alcohols used were ethanol, 1-propanol, and 1-butanol. The calorimetric results reveal that the interaction of short-chain alcohols with the lipid bilayer is endothermic and strongly dependent on the lipid bilayer composition. In the presence of high concentrations of cholesterol, the binding enthalpy of ethanol is decreased, whereas the presence of ceramides enhances the enthalpic response of the lipid bilayer to ethanol. Isothermal titration calorimetry offers a new methodology of investigating molecular interactions and for determining partitioning coefficients for alcohols into lipid bilayers. We have estimated the partitioning coefficients for the three alcohols between the aqueous phase and the lipid bilayers of various lipid composition on the basis of calorimetric results.

KW - Alcohol-liposome interaction

KW - Isothermal titration calorimetry

KW - Lipid composition

KW - Partitioning coefficients

KW - Temperature dependence

UR - http://www.scopus.com/inward/record.url?scp=0000097516&partnerID=8YFLogxK

U2 - 10.1016/S0040-6031(98)00633-9

DO - 10.1016/S0040-6031(98)00633-9

M3 - Journal article

AN - SCOPUS:0000097516

VL - 328

SP - 129

EP - 135

JO - Thermochimica Acta

JF - Thermochimica Acta

SN - 0040-6031

IS - 1-2

ER -