Reduction of ubiquinone by lipoamide dehydrogenase: An antioxidant regenerating pathway
2001 (English)In: European Journal of Biochemistry, ISSN 0014-2956, E-ISSN 1432-1033, Vol. 268, no 5, 1486-1490 p.Article in journal (Refereed) Published
Lipoamide dehydrogenase belongs to a family of pyridine nucleotide disulfide oxidoreductases and is ubiquitous in aerobic organisms. This enzyme also reduces ubiquinone (the only endogenously synthesized lipid-soluble antioxidant) to ubiquinol, the form in which it functions as an antioxidant. The reduction of ubiquinone was linear with time and exhibited turnover numbers of 5 and 1.2 min-1 in the presence and absence of zinc, respectively. The reaction was stimulated by zinc and cadmium but not by the other divalent ions tested. The zinc/cadmium-dependent stimulation of the reaction increased rapidly and linearly up to a concentration of 0.1 mM and was even further increased at 0.5 mM. At pH 6, the activity was three times higher than at physiological pH. Alteration of the NADPH : NADP+ ratio revealed that the reaction is inhibited by higher concentrations of the oxidized cofactors. FAD reduced ubiquinone in a dose-dependent manner at a considerably lower rate, suggesting that the reduction of ubiquinone by lipoamide dehydrogenase involves the FAD moiety of the enzyme.
Place, publisher, year, edition, pages
2001. Vol. 268, no 5, 1486-1490 p.
Antioxidants, Lipoamide dehydrogenase, Oxidative stress, Ubiquinone, Zinc, antioxidant, cadmium, dihydrolipoamide dehydrogenase, nicotinamide adenine dinucleotide phosphate, oxidoreductase, reduced nicotinamide adenine dinucleotide phosphate, article, controlled study, dose response, high performance liquid chromatography, priority journal, reduction, Animals, Cations, Divalent, Chromatography, High Pressure Liquid, Coenzymes, Flavin-Adenine Dinucleotide, Heart, Hydrogen-Ion Concentration, Kinetics, Lipid Peroxidation, NAD, NADP, Oxidation-Reduction, Swine
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:sh:diva-24014DOI: 10.1046/j.1432-1327.2001.02013.xISI: 000167601900037PubMedID: 11231302ScopusID: 2-s2.0-0035087829OAI: oai:DiVA.org:sh-24014DiVA: diva2:722117