Which enzymes are primarily involved in the regulatory steps of the Citric Acid Cycle?

The enzymes primarily involved in the regulatory steps of the Citric Acid Cycle are isocitrate dehydrogenase and alpha-ketoglutarate dehydrogenase. These enzymes are critical for controlling the flow of metabolites through the cycle and play a significant role in regulating the overall rate of cellular respiration.

Isocitrate dehydrogenase catalyzes the conversion of isocitrate to alpha-ketoglutarate, which is a key point of regulation influenced by the levels of ATP and NADH. When energy levels are high, the activity of this enzyme decreases, while low energy levels stimulate its activity, ensuring that the cycle operates efficiently according to the cell's energy needs.

Similarly, alpha-ketoglutarate dehydrogenase acts as a regulatory point as it converts alpha-ketoglutarate into succinyl-CoA. This reaction is also sensitive to the energy status of the cell, with the concentrations of NADH and succinyl-CoA affecting the activity of the enzyme.

Both of these enzymes serve as checkpoints that can adjust the speed of the cycle based on the energy demand of the cell, making them integral to metabolic regulation.