skip to main content

Title: Effect of fatty acyl chain length and structure on the lamellar gel to liquid-crystalline and lamellar to reversed hexagonal phase transitions of aqueous phosphatidylethanolamine dispersions

The lamellar gel/liquid-crystalline and the lamellar liquid-crystalline/reversed hexagonal phase transitions of aqueous dispersions of a number of synthetic phosphatidylethanolamines containing linear saturated, branched chain, and alicyclic fatty acyl chains of varying length were studied by differential scanning calorimetry, {sup 31}P nuclear magnetic resonance spectroscopy, and X-ray diffraction. For any given homologous series of phosphatidylethanolamines containing a single chemical class of fatty acids, the lamellar gel/liquid-crystalline phase transition temperature increases and the lamellar liquid-crystalline/reversed hexagonal phase transition temperature decreases with increases in hydrocarbon chain length. For a series of phosphatidylethanolamines of the same hydrocarbon chain length but with different chemical structures, both the lamellar gel/liquid-crystalline and the lamellar liquid-crystalline/reversed hexagonal phase transition temperatures vary markedly and in the same direction. These results suggest that for any given hydrocarbon chain length, there may be a critical thickness at which the liquid-crystalline phosphatidylethanolamine bilayer becomes unstable with respect to inverted nonbilayer phases such as the H{sub II} phase and that the temperature at which this critical thickness is reached is dependent upon that bilayers proximity to the hydrocarbon chain-melting phase transition temperature.
Authors:
; ; ; ;  [1]
  1. (Univ. of Alberta, Edmonton (Canada))
Publication Date:
OSTI Identifier:
5640343
DOE Contract Number:
FG02-87ER60522
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemistry; (USA); Journal Volume: 28:2
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; MEMBRANES; CONFORMATIONAL CHANGES; PHOSPHOLIPIDS; PHASE STUDIES; AMINES; AQUEOUS SOLUTIONS; CALORIMETRY; NUCLEAR MAGNETIC RESONANCE; PHOSPHORUS 31; PROTONS; TEMPERATURE DEPENDENCE; X-RAY DIFFRACTION; BARYONS; COHERENT SCATTERING; DIFFRACTION; DISPERSIONS; ELEMENTARY PARTICLES; ESTERS; FERMIONS; HADRONS; ISOTOPES; LIGHT NUCLEI; LIPIDS; MAGNETIC RESONANCE; MIXTURES; NUCLEI; NUCLEONS; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; ORGANIC PHOSPHORUS COMPOUNDS; PHOSPHORUS ISOTOPES; RESONANCE; SCATTERING; SOLUTIONS; STABLE ISOTOPES 550602* -- Medicine-- External Radiation in Diagnostics-- (1980-)