Supercooled Water and Ice Included in Multilamellar L-α, Distearoyl Phosphatidylcholine in Low-Temperature Regions below 0℃

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概要

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• Bilayer, supercooled water and ice states in multilamellar phospholipids are investigated in the low-temperature region from 0℃ to -100℃ using L-α, distearoyl phosphatidylcholine(DSPC)having water contents of 44 wt% and 15 wt%, by differential scanning calorimeter and X-ray diffraction methods. Multilamellar DSPC contains 44 wt% water in not only the water layer, but also as excess water in the form of stock regions ; on the other hand, multilamellar DSPC containing 15 wt% water has no excess water. The difference in water content between these multilamellar DSPCs causes characteristic changes of the H_2O molecules and of the phospholipid bilayer in low-temperature regions below 0℃, e.g., ice crystallization inside or outside the multilamellae, changes in the chain packing conformation and changes in the long-range distance. It is confirmed that the supercooled water in the water layer inside multilamellar DSPC containing 15 wt% water continues to exist down to about -45℃ during the cooling process and then is frozen into heterogeneous ice or ice nuclei below about -45℃. In the case of multilamellar DSPC with 44 wt% water, although changes of excess water from supercooled water to homogeneous ice with hexagonal symmetry are observed at about -20℃, the water layer inside the multilamellae remains supercooled down to about -45℃. Dehydration of polar head groups due to the appearance of ice in the water layer at around -45℃ promotes some movement of polar head groups, thereby inducing changes in the chain packing conformation.

• 社団法人応用物理学会の論文
• 2000-10-15

著者

• Utoh Shigenori

  Department Of Applied Physics Faculty Of Engineering Kyushu University

• OKUBO Nobuaki

  Analytical Applications Laboratory, Scientific Instruments Division, Seiko Instruments Inc.

• Okubo Nobuaki

  Analytical Applications Laboratory Scientific Instruments Division Seiko Instruments Inc.

関連論文

• Phase Transition of Lipid Multilameller Aqueous Suspension under High Pressure. : II. Structural Analyses of Lipid Bimembrane under High Pressure by X-Ray Studies
• Phase Transition of Lipid Multilamellar Aqueous Suspension under High Pressure : III. Laser Raman Spectroscopic Study of Dipalmitoyl Phosphatidylcholine Bimembrane under High Pressure
• Changes in Hydrocarbon Chains and Head Groups in Distearoyl Phosphatidylcholine at 4th and 3rd Transitions under High Pressure
• Phase Transition of Lipid Multilamellar Aqueous Suspension under High Pressure : I. Investigation of Phase Diagram of Dipalmitoyl Phosphatidylcholine Bimembrane by High Pressure-DTA and -Dilatometry
• Supercooled Water and Ice Included in Multilamellar L-α, Distearoyl Phosphatidylcholine in Low-Temperature Regions below 0℃
• β-Relaxation Phenomena of Copolymer of Polyvinylidene and Trifluoroethylene

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