Unit cell volume and liquid-phase immiscibility in oleate-stearate lipid mixtures

作者：Schmidt Walter F^*; Mookherji Swati; Crawford Michael A

来源：Chemistry and Physics of Lipids, 2009, 158(1): 10-15.

DOI：10.1016/j.chemphyslip.2008.12.005

• Cubic unit cell volume
• Oleic acid
• Methyl oleate
• Stearic acid
• Immiscible lipid phases
• Cloud point
• Stoichiometry

The structural basis of immiscibility of stearic acid (SA) in two unsaturated lipids at room temperature was examined. A 5% SA mixture in octadec-9-enoic acid (OA) is cloudy; a 5% SA solution in the methyl ester of OA (MeOA) is fully miscible. At 10% SA in MeOA, a clear and immiscible phase formed. The composition of this immiscible phase however was not 10% SA, but 25% SA. Adding additional SA altered the amount of the second phase, not its stoichiometry. Molecular mechanics explains the molecular basis for the ratio of saturated and unsaturated lipids in the different phases. Packing order of lipids within a unit volume explains the discrete lipid composition ratio forming each of the observed miscible and immiscible phases. The smallest unit cell volume that explains the observed stoichiometry is a cube (not a sphere). Published by Elsevier Ireland Ltd

• 出版日期2009-3