Changes in mitochondrial form

THE EFFECT OF RIBOFLAVIN DEFICIENCY AND GALACTOFLAVIN FEEDING ON OXIDATIVE PHOSPHORYLATION AND RELATED REACTIONS IN RAT LIVER MITOCHONDRIA

The effect of riboflavin deficiency and feeding of galactoflavin on the flavin content of liver mitochondria, oxidative phosphorylation, Pi–ATP exchange, and ATPase activity was studied. Both dietary riboflavin deprivation and galactoflavin feeding resulted in a depressed flavin content of mitochondria, the latter treatment resulting in a more severe flavin loss. P/O ratios under all treatments were normal as were Pi–ATP exchange rates and the oxidation of succinate. Glutamate and β-hydroxybutyrate oxidations were depressed in mitochondria from rats fed galactoflavin for 15 or 28 days. DNP-activated ATPase was elevated in both flavin-deficient and galactoflavin-fed preparations while Mg++-activated ATPase was depressed in the galactoflavin-fed preparations. These results are discussed in relation to the hypothesis that flavin is involved in energy conservation in the diaphorase region of electron transport.