title: Barotropic phase transition between the lamellar liquid crystal phase and the inverted hexagonal phase of dioleoylphosphatidylethanolamine.
abstract: The phase transition between the lamellar liquid crystal (Lalpha) phase and the inverted hexagonal (H(II)) phase of dioleoylphosphatidylethanolamine (DOPE) in aqueous NaCl solutions was observed by means of differential scanning calorimetry (DSC) under ambient pressure and light-transmittance technique under high pressure. The pressure dependence of the transition temperature (dT/dp) and the thermodynamic quantities for the Lalpha/H(II) transition were compared with those of another phase transition found in the DOPE bilayer membrane, which is the transition from the lamellar crystal (Lc) phase to the Lalpha phase. The dT/dp value of the Lalpha/H(II) transition was about 3.5 times as large as that of the Lc/Lalpha transition while the thermodynamic quantities were significantly smaller than those of the latter to the contrary. Comparing the enthalpy and volume behavior of the Lalpha/H(II) transition with that of the Lc/Lalpha transition, we concluded that the Lalpha/H(II) transition can be regarded as the volume-controlled transition for the reconstruction of molecular packing.
authors.affiliation: Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, Tokushima 770-8506, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Sueyoshi
authors.forename: Kaori
authors.initials: K
authors.lastname: Tada
authors.forename: Masaki
authors.initials: M
authors.lastname: Goto
authors.forename: Nobutake
authors.initials: N
authors.lastname: Tamai
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Matsuki
authors.forename: Shoji
authors.initials: S
authors.lastname: Kaneshina
mesh_terms: D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D008051:Lipid Bilayers / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D008954:Models, Biological; D044367:Phase Transition; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D010714:Phosphatidylethanolamines; D012996:Solutions; D014867:Water; C094877:dioleoyl phosphatidylethanolamine; D012965:Sodium Chloride