Terpenylnaphthoquinones are reductively activated by NADH/NADH dehydrogenase |
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| Authors: | Antonio E. Alegria Sheila Sanchez Pedro Sanchez-Cruz Ileana Nieves Nadya G. Cruz Marina Gordaliza |
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| Affiliation: | 1. Department of Chemistry , University of Puerto Rico at Humacao , Humacao, Puerto Rico 00791ae_alegria@webmail.uprh.edu;3. Department of Chemistry , University of Puerto Rico at Humacao , Humacao, Puerto Rico 00791;4. Departamento de Química Farmacéutica , Campus Miguel de Unamuno , Facultad de Farmacia, 37007 Salamanca, Spain |
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| Abstract: | Novel terpenylnaphthoquinones were found to enhance the rate of oxygen consumption in the presence of NADH/NADH dehydrogenase in 1?:?1?v/v mixtures of 40?mM phosphate buffer (pH 7.4) and DMSO. Initial rates of oxygen consumption increase with an increase in the half-wave reduction potentials of the quinones. The amounts of spin trapped methyl radicals in the presence of DMSO, produced through the Haber–Weiss reaction of the oxygen consumption process, and of the corresponding semiquinones, generated under anaerobic conditions, also correlate with the quinone redox potential. Since this enzymatic system is found in mitochondria, a possible pathway in the cytotoxic activity of these terpenylnaphthoquinones could be the interference or inhibition of mitochondrial respiration by NADH depletion or by mitochondrial degradation due to reactive oxygen species generation. |
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| Keywords: | Semiquinone NADH dehydrogenase terpenylnaphthoquinone redox cycling |
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