Partition of CoQ-homologs in lipid membranes.

After studies on incorporation of Coenzyme-Q-homologs into mitochondrial membranes, we have undertaken the same investigation on phospholipid vesicles in order to know the behavior of different Ubiquinones in the biphasic system lipid membrane/H2O. Using concentrations of egg lecithin corresponding to the phospholipid content of 1 mg mitochondrial protein, it was found that some homologs are partitioned in lipid vesicles nearly the same as they are incorporated by mitochondria, while others behave differently. On the basis of the results it is possible to calculate approximately partition coefficients for each Q-homolog. This work shows that also membrane structure, besides the partition membrane/water, affects the incorporation of Ubiquinones.