On the oxidation of reduced nicotinamide dinucleotide phosphate by submitochondrial particles from beef heart

The oxidation of NADPH catalyzed by submitochondrial particles from beef heart in the absence and presence of NAD⁺ has been investigated. The data confirm earlier findings in this laboratory concerning the occurrence of an NADPH dehydrogenase with 2,6-dichlorophenolindophenol as the electron acceptor. This reaction is highly sensitive to palmityl-CoA, a feature further substantiating its possible relationship to nicotinamide nucleotide transhydrogenase. The particles also catalyzed a very low NADPH oxidase activity which probably proceeds via NADH dehydrogenase and is unrelated to transhydrogenase.