36. All of the following characterize phosphofructokinase-1 (PFK-1) EXCEPT (A) the most important regulatory site in glycolysis (B) ATP increases the affinity of the enzyme for fructose-6-phosphate (C) PFK-1 activity is a function of the energy charge of the cell (D) AMP decreases the Km of PFK-1 for fructose-6-phosphate (E) the subunits of PFK-1 behave cooperatively