Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate, an early step of glycolysis. in the presence of oxygen, an increase in the amount of atp in a cell would be expected to a. activate the enzyme and thus increase the rates of glycolysis and the citric acid cycle. b. activate the enzyme and thus slow the rates of glycolysis and the citric acid cycle. c. inhibit the enzyme and thus increase the rate of glycolysis and the concentration of citrate. d. inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle. e. inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycl