Glucokinase (GCK1) reversibly binds glucokinase regulatory protein (GKRP) to form an inactive complex. Binding is stimulated by fructose 6-phosphate and sorbitol 6-phosphate (hence high concentrations of these molecules tend to reduce GCK1 activity) and inhibited by fructose 1-phosphate (hence a high concentration of this molecule tends to increase GCK1 activity) (Brocklehurst et al. 2004).
