Effect of diet and starvation on the activity state of branched-chain 2-oxo-acid dehydrogenase complex in rat liver and heart.

In rats fed a high-protein diet, the branched-chain 2-oxo-acid dehydrogenase complex in liver was essentially fully active and its activity state was unaffected by subsequent starvation for 48 h. Feeding with a low-protein diet led to a decrease in the activity state which was essentially reversed by 48 h of starvation. In heart, the enzyme was primarily inactive (activity state 18%) in rats fed a high-protein diet, with both low-protein diet and starvation leading to a further decrease in the activity state.