The binding saturation of this protein is defined by Hüfner’s constant. Ligand saturation was incorporated in an equation to explain rates of successive binding to this protein by Gilbert Smithson Adair after observing its unusual Hill coefficient. (15[2])The larger binding pocket of this protein when unbound allows 2,3-BPG to function as an allosteric effector. Upon binding, the conformation of this protein changes from its T, or (*) tense, state to its R, or relaxed, state. The “fetal” form of this protein replaces the two beta subunits of its tetrameric structure with two gamma subunits. Perpendicular bond formation with the porphyrin ring in this protein’s binding site leads carbon monoxide to bind (10[1])to it with 250 times more affinity than oxygen. For 10 points, name this iron-containing protein found in blood. ■END■