Answer
Isocitrate dehydrogenase of the citric acid cycle and phosphofructokinase of glycolysis is regulated through feedback inhibition. The only difference in the feedback inhibition between isocitrate dehydrogenase and phosphofructokinase is that NADH inhibits isocitrate dehydrogenase by competitive inhibition, whereas allosteric inhibition regulates phosphofructokinase.
Work Step by Step
Allosteric inhibition and competitive inhibition differ in the inhibitor binding to the enzyme. Allosteric inhibitors bind to a site different from the active site and introduce a conformational change in the enzyme that hinders substrate binding to the active site.
Competitive inhibitors bind to the active site and inhibit substrate binding to the active site. Usually, the substrate affinity would be high in the active site. A higher concentration of the inhibitor leads to the inhibitor binding to the active site and subsequent inhibition of the enzyme.
