| Abstract: | Feeding a fat-free diet for 3 weeks decreases the activity of ascorbate:ferricytochrome b5 oxidoreductase and increases NADH:monodehydroascorbate oxidoreductase in rat liver microsomes. Contrary to Vmax, the apparent Km for monodehydroascorbate of the first enzyme was not depressed. The activity of ascorbate:ferricytochrome b5 oxidoreductase is increased by incubation with microsomal lipid extract, thus showing that the loss of activity results from dietary-induced changes of microsomal fatty acid composition. |
