The addition of small amounts of oxaloacetate or malate to suspensions of minced pigeon-breast muscle stimulated the oxygen consumption of the preparation. Surprisingly, whenever the amount of oxygen consumed was measured, it was around 7 times more than the amount required oxidizing the added oxaloacetate or malate completely to carbon dioxide and water.
a) Explain why does the addition of oxaloacetate or malate stimulate the oxygen consumption?
b) Explain why is the amount of oxygen consumed so much greater than the amount essential to oxidize the added oxaloacetate or malate fully?