Cellular Respiration Regulation

     The reactions of aerobic respiration are regulated by various feedback inhibition and product activation loops. Phosphofructokinase is an important control enzyme in the regulation of cellular respiration.

1)    The catalyst phosphofructokinase at the third reaction of glycolysis is inhibited by ATP from the final product, while it is also stimulated by ADP. Less ATP will be produced when ATP levels are high and ADP levels are low, vice versa.

2)   If the first product of the Krebs cycle, citrate, is accumulated in the mitochondria, some will pass into the cytoplasm and inhibit phosphofructokinase in the glycolysis. As citrate is used and deceased in its concentration, phosphofructokinase inhibition will be reduced, and the rate of glycolysis will increase.

3)   When there is a high concentration of NADH, it indicates that the electron transport chains are full of electrons and ATP production is high. In this case, NADH will inhibit pyruvate decarboxylase and reduces the amount of acetyl-CoA in the process of pyruvate oxidation.