Functional characterization of hESC-derived erythroid cells. (A) Oxygen equilibrium curves of normal human RBCs and human ESC-derived erythroid cells. The 2 curves are virtually indistinguishable at their midpoints, whereas the curve of human ESC-derived erythroid cells is leftward shifted at low (→) and high (▾) oxygen saturation percentages. (B) The Bohr effect. (C) Effects of 2,3-DPG depletion. The solid lines represent the normal RBC control; dashed lines, the human ESC-derived erythroid cells. For each pair, the line on the right represents the fresh cells and the one to the left is the curve from cells depleted of 2,3-DPG.