Phosphofiuctokinase-I
Phosphofiuctokinase-I is activated by AMP and inhibited by ATP and citrate. When ATP is utilized in energy requiring process, the concentration ofAMP is highly increased. Thus a large increase in AMP acts as ametabolic amplifier of a small change in ATP. This mechanism allows the activity of phosphofructokinase-1 to be highly sensitive to even small changes in energy status ofthe cell and to control the quantity of carbohydrate undergoing glycolysis prior to its entry into citric acid cycle. The increase in AMP also explains why glycolysis is increased during hypoxia when ATP decreases.