Mitapivat is an allosteric activator of PK.Top panel: the sigmoid-shaped dependence of PK activity on the concentration of AG-348 (mitapivat) suggests cooperative interaction among the PK subunits. Bottom panel: diagram of the three-dimensional structure of the PK tetramer with bound mitapivat (gray). Blue: the substrate phosphoenolpyruvate PEP; brown: the physiological activator fructose-1,6-bisphosphate (FBP). Modified from Kung et al.⁵²