Addition of small amounts of oxaloacetate or malate to suspensions of minced pigeon-breast muscle stimulated the oxygen consumption of the preparation. Surprisingly, when the amount of oxygen consumed was measured, it was about 7 times more than the amount necessary to oxidize the added oxaloacetate or malate completely to carbon dioxide and water.
(a) Why does the addition of oxaloacetate or malate stimulate oxygen consumption?
(b) (b) Why is the amount of oxygen consumed so much greater than the amount necessary to oxidize the added oxaloacetate or malate completely?
(a) First of all, we need to understand what oxygen consumption corresponds to. It is an indirect measurement of the activity of glycolysis and the citric acid cycle. Of course, generally speaking, the main molecules being oxidized are carbohydrates and lipids, right? However, since several intermediates in the Krebs cycle can be siphoned off into various biosynthetic pathways, the cycle may slow down for lack of oxaloacetate (OAA) when there are other ...
This solution explains by oxaloacetate stimulates oxygen consumption and how that relates to oxidization.