Which substance serves as a powerful inhibitor of glycolysis by increasing ATP levels?

Citrate plays a significant role in cellular metabolism and acts as a powerful inhibitor of glycolysis, particularly in the liver. When levels of ATP are high in the cell, citrate is accumulated, signaling that the energy needs of the cell are being met. This results in the inhibition of key glycolytic enzymes, such as phosphofructokinase-1 (PFK-1), which is a crucial regulatory enzyme in the glycolytic pathway.

Citrate's inhibitory effect on glycolysis is part of a broader regulatory mechanism that balances energy production and consumption. High concentrations of citrate not only signal that there is enough energy available, but they also promote the diversion of metabolic intermediates towards fatty acid and lipid synthesis, which further emphasizes the energy-storage state of the cell.

High ATP levels, indicated by an accumulation of citrate, create a negative feedback loop, thus reducing the activity of glycolysis to prevent excessive glucose breakdown when energy is already plentiful. This inhibition aids in maintaining homeostasis within the cell and ensures that energy production aligns with cellular requirements.