ATP, citrate, or glucose-6-phosphate

1.) Increases in NADH, Succinyl CoA, ATP, Citrate inhibit citrate synthase.

2.) Increases in ATP will inhibitisocitrate dehydrogenase.

3.) Increases in succinyl CoA and NADH will inhibit succinate thiokinase.

Citrate synthase is inhibited by ATP. Obviously, the Krebs cycle produces ATP. This is the first step and one of the major regulatory steps in the pathway. If the cell has plenty of ATP, then it wouldn't need to keep making it, thus the pathway needs to be shut off. ATP inhibits the enzyme to shut off the pathway. This is an example of feedback inhibition (you can also call it negative inhibition or even product inhibition). Feedback inhibition is when the products of a certain biochemical pathway inhibit earlier enzymes, shutting down the pathway.

Glucokinase is the enzyme responsible for phosphorylation of glucose in the first step of glycolysis. The glucokinase complex is modified by two different molecules: citrate and ATP. Citrate and ATP are both products of the sequence of reactions in aerobic respiration and are consequently products of glycolysis. As these two molecules' concentrations in the cell build up, they bind to the allosteric site of glucokinase and shut it down.

3 ATP, 6 CO2, 9 NADH, and 3 FADH2