Mitochondrial NADH oxidase activity of Setaria cervi.

The bovine filarial parasite, Setaria cervi, has been found to contain NAD(P)H oxidase activity. The system was predominantly located in the mitochondrial membranes, with very little activity available in the soluble fraction of the organelle. The membrane preparation also exhibited the presence of a reduced pyridine nucleotide transhydrogenase which converted NADPH into NADH by transferring a hydride ion. The oxidase activity was inhibited by all the respiratory inhibitors examined, with the greatest sensitivity to rotenone, a site I-specific inhibitor. The system was also found to be susceptible to exposure to anthelmintics, amongst which levamisole proved the most effective.