ABSTRACT
The wide distribution of ubiquinones (UQ) in almost all biological systems suggests a major role of this biomolecule in the maintenance of homeostasis.
The isoprenic side chain, which is linked to the benzoquinone head group, anchors the molecule in the lipid phase of biological membranes. Nevertheless, UQ is inhomogenously distributed in biomembranes. This observation indicates that loading of the various biomembranes with UQ is actively regulated rather than being a result of passive partitioning. This fact strongly suggests that in some membranes, UQ is more than a building block of the membrane architecture, although UQ is thought to contribute to the structural integrity of biomembranes. The highest values of UQ are found in mitochondria, Golgi vesicles, and lysosomes.
