Fig. 3. The effects of various ions on the cooperativity (n₅₀) of Haliotis iris haemocyanin O₂-binding at 15°C. Labels in the legend refer to the concentrations (mmol l^–1) of Ca²⁺ (Ca), Mg²⁺ (Mg), D-lactate (D-l), and L-lactate (L-l). nh, native haemolymph; dHc, dialysed Hc without added cofactor.