Discuss the regulation of the citric acid cycle by oxaloacet

Discuss the regulation of the citric acid cycle by oxaloacetate.

Describe the major components of the electron transport chain. How would the following conditions affect ATP production by the electron transport chain?

Abundance of NADH and O2

Cyanide added

Lack of O2

Solution

1). Citric acid cycle regulation by oxaloacetate:

The 8th step in citric acid cycle (malate + NAD+ oxaloacetate + NADH + H+) is highly exergonic, and the oxaloacetate formed during this reaction is continuously removed out, which maintains the extreme low concentrations of oxaloacetate in the cell. This favors the malate dehydrogenase reaction to proceed and form oxaloacetate. Thus, the cycle continues (means the oxaloacetate formation catalyzes the citric acid cycle). If oxaloacetate is removed, the flow of carbon is inhibited, which ultimately decrease ATP production.