Oxygen equilibrium curves and Hill coefficients for human embryonic and semi-embryonic hemoglobins.

Oxygen equilibrium curves are displayed in panels A-C. (A) Human Hb Gower-1 (ζ₂ε₂). (B) Human Hb Gower-2 (α₂ε₂). (C) Human Hb Portland-2 (ζ₂β₂). OECs were established for affinity-purified human hemoglobins under standard assay conditions (“Materials and methods”). Representative curves (black) are displayed with an OEC from control human Hb A for reference (gray). P₅₀ values derived from analyses of these curves are included in Table 1. Hill coefficients are displayed in panels D-F. (D) Human Hb Gower-1 (ζ₂ε₂, ⧫). (E) Human Hb Gower-2 (α₂ε₂, ●). (F) Human Hb Portland-2 (ζ₂β₂, ■). Hill plots constructed from OECs of human hemoglobins in panels A to C are illustrated along with control human Hb A (O). Hill coefficients derived from these curves are included in Table 1.