Now, eventually, after we form many ATP molecules and the concentration of ATP rises and the energy charge of the cell increases, we will not want to form any more ATP molecules. Because what that will mean is not only will we have enough ATP molecules to go around, we'll also have enough citrate molecules to actually create ATP molecules. And so in this particular case if we have plenty of ATP molecules that means we'll have plenty of Pyruvate molecules and plenty of citrate molecules circling in that crept cycle. And so if we have a high citrate concentration in the cytoplasm, that citrate will go on and buy until phosphorptokinase and it will basically increase the ability of the ATP to actually inhibit the phosphorptokinase. And so just like ATP, citrate is also an allosteric inhibitor to the phosphorptokinase. And this is the second important difference between the phosphorptokinase in skeletal muscle cells and the one in liver cells.