Affiliations: Fundamental Pharmacology and Toxicology, University of
Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
Note: [] Address for correspondence: Prof. Dr. Hans Nohl, Fundamental
Pharmacology and Toxicology, University of Veterinary Medicine Vienna,
Veterinärplatz 1, A-1210 Vienna, Austria. Tel.: +43 1 25077 4400; Fax: +43 1
25077 4491; E-mail: hans.nohl@vu-wien.ac.at
Abstract: The chemistry of ubiquinone allows reversible addition of single
electrons and protons. This unique property is used in nature for aerobic
energy gain, for unilateral proton accumulation, for the generation of reactive
oxygen species involved in physiological signaling and a variety of
pathophysiological events. Since several years ubiquinone is also considered to
play a major role in the control of lipid peroxidation, since this lipophilic
biomolecule was recognized to recycle α-tocopherol
radicals back to the chain-breaking form, vitamin E. Ubiquinone is therefore a
biomolecule which has increasingly focused the interest of many research groups
due to its alternative pro- and antioxidant activity. We have intensively
investigated the role of ubiquinone as prooxidant in mitochondria and will
present experimental evidences on conditions required for this function, we
will also show that lysosomal ubiquinone has a double function as proton
translocator and radical source under certain metabolic conditions.
Furthermore, we have addressed the antioxidant role of ubiquinone and found
that the efficiency of this activity is widely dependent on the type of
biomembrane where ubiquinone exerts its chain-breaking activity.
