Dithranol, Glucose-6-phosphate Dehydrogenase Inhibition and Active Oxygen Species

K. Müller, M. Seidel, C. Braun, K. Ziereis, Wolfgang Wiegrebe
Inhibition of glucose-6-phosphate dehydrogenase (G6- PDH) by dithranpl (anthralin, CAS 480-22-8) has been studied in the presence of catalase, superoxide dismutase (SOD) and various scavengers of active oxygen species. Most scavengers were found to be either inhibitors of G6- PDH by themselves or simply without effect. The combined addition of catalase and SOD as well as the heatdenatured enzymes and the oxygen radical scavengers atocopherol and salicylic acid markedly reduced the inhibitory
more » ... d the inhibitory effect of dithranol. The direct exposure of G6-PDH to active oxygen species led to different results. When liberated from a water-soluble naphthalene endoperoxide, singlet oxygen was without effect whereas photosensitization with methylene blue resulted in a total loss of enzyme activity. Experiments under anaerobic conditions revealed that this inhibition was accomplished by the triplet state of the sensitizer. Superoxide anion radical was highly effective at concentrations corresponding to the amount of that produced by a 10 nmol/l dithranol solution. In contrast, hydroxyl, alkylperoxyl and alkoxyl radicals were all less efficient. H202 and alkylhydroperoxides did not alter the enzyme activity. The results suggest that O2 is the potent species towards G6-PDH, if dithranol acts through formation of active oxygen species. Glucose-6-phosphat-Dehydrogenase (G6-PDH)-Hemmung durch Dithranol (Anthralin, CAS 480-22-8) wurde in Gegenwart von Catalase, Superoxid-Dismutase (SOD) und verschiedenen Fängern für aktive Sauerstoffspezies untersucht. Die meisten Fänger waren entweder selbst Hemmstoffe der G6-PDH oder wirkungslos. Sowohl die kombinierte Zugabe von Catalase und SOD als auch die denaturierten Enzyme, ebenso die Sauerstoffradikalfänger a-Tocopherol und Salicylsäure zeigten eine deutliche Reduzierung der durch Dithranol verursachten Hemmefi fekte. Die direkte Einwirkung von aktiven Sauerstoffspezies auf G6-PDH führte zu unterschiedlichen Resultaten. Freisetzung von Singulett-Sauerstoff aus einem wasserlöslichen Endoperoxid war o [...]
doi:10.5283/epub.15735 fatcat:leo327zulbfrdlzlk22nrhbrt4