Isocitrate oxidation in dog heart mitochondria under anoxic conditions

The roles of NAD- Specific Isocitrate Dehydrogenase (NAD- IDH) (EC 1.1.1.4), NADP- Specific Isocitrate Dehydrogenase (NADP- IDH) (EC 1.1.1.42) and Piridin Nucleotide Transhydrogenase (Transhydrogenase) (EC 1.6.1.1) in the mitochondrial oxidation of isocitrate through the respiratory chain in conditions of normal and increased energy requirements have been studied in submitochondrial particles isolated from healthy and ischemic dog hearts. The activities of both, NAD- IDH and NADP- IDH were increased in conditions of anoxia, while Transhydrogenase remained unchanged. The results obtained showed that the mitochondrial oxidation of isocitrate in dog myocardium occurs mainly through the NAD- IDH pathway in normoxic and anoxic conditions.