PHOSPHORYLATIVE AND NONPHOSPHORYLATIVE PATHWAYS OF ELECTRON TRANSFER IN RAT LIVER MITOCHONDRIA

Abstract
Removal of pyri-dine nucleotides from rat liver mitochondria, followed by the addition of TPN and isocitrate, shows that TPNH oxidation does not result in phosphorylation, but that oxidation of DPNH (generated from the oxidation of glutamate) in the same preparation does. Cytochrome c is reduced more rapidly by mitochondrially generated DPNH than with TPNH. The role of pyridine nucleotide transhydrogenase in rat liver mitochondria was investigated, and a scheme that involves this enzyme as a regulator of respiration and of energy-releasing reactions is presented.