2001 Fiscal Year Final Research Report Summary
Role of water molecules in appearance of the gel and subgel phases in lipid bilayer systems
| Project/Area Number |
12640568
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
機能・物性・材料
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| Research Institution | Okayama University of science |
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Principal Investigator |
KODAMA Michiko Okayama University of Science, Professor, 理学部, 教授 (40101282)
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| Co-Investigator(Kenkyū-buntansha) |
AOKI Hiroyuki Okayama University of Science, Associate Professor, 理学部, 講師 (80248202)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Phospholipid Bilayer / interlamellar water / Differential Scanning Calorimetry / 2^H-NMR Spectroscopy / 2^H-Spin-latticerelaxation time / ice-melting enthalpy / Deconvalution analysis |
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| Research Abstract |
Phospholipids are major components of biomembranes and constitute a fundamental part of their bilayer structure. Studies of water behavior in phospholipid bilayer systems are the subject of many investigations, From this viewpoint, in the present study, the numbers of three types of differently bound water molecules (nonfreezable interlamellar, freezable interlamellar and bulk water molecules) in the gel and the subgel phase of phospholipid bilayer systems were estimated from a deconvolution analysis of the ice-melting DSC curves and were used to construct a water distribution diagram of the two phases, i.e., a plot of the cumulative number of the respective water molecules (per lipid molecule) against H20/DPPC molar ratio. Furthermore, 2H-NMR study was performed for the D20-lipid bilayer systems with a high resolution liquid NMR apparatus and the longitudinal (spin-lattice) relaxation time (21) of 2H nuclei for the D20 molecules was measured at 5 ーC using a pulse program of 180 ー- r-90 ー. By fitting the equation of magnetization versus delay time to experimental inversion recovery data, both components and compositions of differently bound freezable water molecules were estimated and were compared between the gel and the subgel phase.
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