Occurrence of oxygen-sensitive, NADP+-dependent pyruvate dehydrogenase in mitochondria of Euglena gracilis

Pyruvate dehydrogenase found in mitochondria of Euglena gracilis was active on NADP+ but not NAD+, and FAD and methyl viologen also served as electron acceptors. For 2-oxoglutarate dehydrogenase both NAD+ and NADP+ were utilized and the ratio of its activity on NAD+ and NADP+ was about 1:5. The activity of pyruvate dehydrogenase was inhibited by pyruvate in aerobiosis, while not in anaerobiosis.