(A) Interaction between purified apomyoglobin and the haem–agarose resin or non-derivatized agarose resin. Fractions were analysed by SDS/PAGE on a 12% gel, followed by silver nitrate staining. The loaded fractions were: haem–agarose resin pass-through after loading (PT), purified apomyoglobin as a control (myo), apomyoglobin eluted from the haem–agarose resin with 8 M urea (E), and control sample eluted after washing from the interaction between the non-derivatized agarose resin and apomyoglobin (C). (B) Interaction between purified IRP2 and the haem–agarose affinity resin: pass-through fraction (PT), first rinse with washing buffer (W) and the material eluted using 8 M urea (E). Molecular masses in kDa are shown on the left.