“…The form s h /(K h d + s h ), where s is the ligand concentration, K d is the dissociation constant, and h is the "cooperativity coefficient" (also known as the Hill coefficient), was proposed by Hill in his analysis of the oxygen transport properties of haemoglobin. This expression describes receptor occupancy well at ligand concentrations approximating to the K d [7][8][9]. However, the Hill expression fails to describe the dynamic range of an activated regulator, such as a TF well.…”