Solubilization of ubiquinone-10 in the lamellar and bicontinuous cubic phases of aqueous monoolein.
Using X-ray diffraction measurements and polarizing microscopy, the solubilization of ubiquinone-10 (UQ10) was investigated in the lamellar and reversed bicontinuous cubic phases of aqueous monoolein (MO, 86 wt% of monooleoylglycerol). At 25 degrees C and UQ10 content below 0.5 wt%, a partial phase diagram of the MO/UQ10/H2O system indicated the same sequence of hydration-induced phases as found in the MO/H2O system. This low amount of coenzyme had no effect on the MO bilayer thickness and swelling behavior of phases, but it promoted thermotropic Q230-->HII phase transition. We suggested that the effect was determined by the UQ10 partitioning into the HII phase regions where the MO chains must be stressed upon the phase transition. At UQ10 contents above 0.5 wt%, a solid 'UQ10-rich' phase appeared inside the initially homogeneous phases within a few days. It was proposed that this process was driven by the coenzyme lateral diffusion in the MO bilayer.
Barauskas
J
J
Institute of Biochemistry, Vilnius, Lithuania.
Razumas
V
V
Nylander
T
T
D003460:Crystallization; D004579:Electron Transport; D005989:Glycerides / Q000737:chemistry*; D008859:Microscopy, Polarization; D008928:Mitochondria / Q000378:metabolism; D012995:Solubility; D013816:Thermodynamics; D014451:Ubiquinone / Q000737:chemistry* / Q000378:metabolism; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
D005989:Glycerides; D014867:Water; D014451:Ubiquinone; C005953:monoolein; C025204:Ubiquinone Q2