title: Spectroscopic properties of ubiquinones in model systems.
abstract: In order to achieve a better elucidation of the physico-chemical properties of ubiquinones (Qs) in natural membranes, we have investigated the UV spectral features of Q-homologs in different model systems. In phospholipid monolamellar vesicles the UV spectra of physiological ubiquinones resemble those in isooctane, whereas in detergent micelles the spectra appear similar to those of the hydrophilic Q1 in water. For short-chain Qs it is possible to describe a linear dependence of the absorption parameters upon the polarity of the media. Long-chain Qs exhibit strong deviations due to aggregation states. In aqueous media a pH dependence of the spectral properties of ubiquinones is also observed. The findings in model systems can provide useful correlations between the spectroscopic properties of ubiquinones, their physico-chemical characteristics in the natural membranes, and rapid spectrophotometric detections of their redox changes.
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D008823:Micelles; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D008567:Membranes, Artificial; D008823:Micelles; D012997:Solvents; D014451:Ubiquinone