Final answer:
IDH is activated by ADP, which increases the rate of the Krebs cycle when the cell's energy levels are low. This regulation is a part of the cell's energy homeostasis mechanism, preventing excess production of ATP when it is not required.
Step-by-step explanation:
IDH (isocitrate dehydrogenase) is allosterically activated by ADP at high concentrations. This interaction is crucial for regulating the Krebs cycle, also known as the citric acid cycle.
When a cell's energy levels are low, indicated by high levels of ADP, IDH is activated, which helps to increase the rate of the Krebs cycle.
This, in turn, leads to the production of more ATP, as the cycle produces vital electron carriers like NADH that are used in the production of ATP through the electron transport chain.
When the cell has sufficient ATP, indicating high energy levels, the Krebs cycle is downregulated.
This prevents the wastage of cellular resources on producing energy that is not needed.
Overall, this regulation by ADD ensures that the cell maintains energy homeostasis by adjusting the rate of the Krebs cycle according to the cell's immediate energy requirements.