Ethanol induces interdigitated gel phase (LβI) between lamellar gel phase (Lβ′) and ripple phase (Pβ′) in phosphatidylcholine membranes: a scanning density meter study

doi:10.1016/0005-2736(90)90169-O

Biochimica et Biophysica Acta (BBA) - Biomembranes

Volume 1028, Issue 3, 19 October 1990, Pages 215-222

https://doi.org/10.1016/0005-2736(90)90169-O Get rights and content

Abstract

Effects of ethanol on dipalmitoylphosphatidylcholine (DPPC) and distearoylphosphatidylcholine (DSPC) dispersions were investigated with an automated scanning density meter and a differential scanning calorimeter (DSC). The temperature-dependent profile of specific volume measured by the density meter clearly exhibited phase transitions of the DPPC and the DSPC dispersions as drastic changes in the thermal expansion coefficients. On increasing the ethanol concentration in the DPPC dispersions, the pretransition temperature was reduced faster than the main transition temperature was. An interdigitated gel phase (L_βI) appeared as a region of lower specific volume at the pretransition temperature when the ethanol concentration reached 40 mg/ml. The L_βI phase spread both its ends in an ethanol-dependent fashion, and the high-temperature end merged to the main transition at 50 mg/ml of ethanol. The temperature-ethanol phase diagram has been determined for DPPC. The transitions from L_β′ to L_βI and from L_βI to P_β′ were also observed on the thermograms of DSC measurements. In the DSPC dispersions, the L_βI phase was induced between the L_β′ and the P_β′ phases by a lower ethanol concentration (about 20 mg/ml).

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Regular paperEthanol induces interdigitated gel phase (LβI) between lamellar gel phase (Lβ′) and ripple phase (Pβ′) in phosphatidylcholine membranes: a scanning density meter study

Abstract

Biochim. Biophys. Acta

Chem. Phys. Lipids

Biochim. Biophys. Acta

Biochim. Biophys. Acta

Biochim. Biophys. Acta

Biochim. Biophys. Acta

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Prog. Lipid Res.

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Anal. Biochem.

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J. Biol. Chem.

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Regular paper
Ethanol induces interdigitated gel phase (L_βI) between lamellar gel phase (L_β′) and ripple phase (P_β′) in phosphatidylcholine membranes: a scanning density meter study