Fig. 5. (Top) Overall oxygenation enthalpies (H') derived using the van't Hoff isochore and P₅₀ values at 10 and 20°C and different pH values (Fig. 3), in the absence of added lactate (A) and the presence of 10 mmol l^–1 lactate (B). (Bottom) The interpolated, pH-dependent difference between these values (B–A).