<P> The regulation of 1 - phosphofructokinase occurs primarily by allosteric effectors , and is based on the cell 's energy needs . There are two ATP binding sites ; a substrate site where the phosphate transfer occurs , and an allosteric site where allosteric regulation occurs . ATP acts as an allosteric inhibitor and when cellular concentrations of ATP are high , and the cell 's energy needs are low , the reaction catalyzed by 1 - phosphofructokinase is inhibited . When the cell is actively consuming ATP and stores deplete , the concentration of ATP lowers while the concentrations of AMP and ADP increase . AMP and ADP are both positive effectors of 1 - phosphofructokinase and bind allosterically to activate the reaction . This activation encourages glycolysis and ATP production . Inhibition can also occur via citrate , a product of glycolysis and intermediate in the citric acid cycle . An increased concentration of citrate indicates the cell is meeting current energy needs , and therefore encourages allosteric inhibition of 1 - phosphofructokinase allosterically via ATP . </P>
<P> The regulation of 1 - phosphofructokinase occurs primarily by allosteric effectors , and is based on the cell 's energy needs . There are two ATP binding sites ; a substrate site where the phosphate transfer occurs , and an allosteric site where allosteric regulation occurs . ATP acts as an allosteric inhibitor and when cellular concentrations of ATP are high , and the cell 's energy needs are low , the reaction catalyzed by 1 - phosphofructokinase is inhibited . When the cell is actively consuming ATP and stores deplete , the concentration of ATP lowers while the concentrations of AMP and ADP increase . AMP and ADP are both positive effectors of 1 - phosphofructokinase and bind allosterically to activate the reaction . This activation encourages glycolysis and ATP production . Inhibition can also occur via citrate , a product of glycolysis and intermediate in the citric acid cycle . An increased concentration of citrate indicates the cell is meeting current energy needs , and therefore encourages allosteric inhibition of 1 - phosphofructokinase allosterically via ATP . </P>
how many binding sites for atp are there in pfk
how many binding sites for atp are there in pfk
two
two