Hemopexin, a heme-binding serum protein, was first described by Neale et al in 1958.1 The high carbohydrate content and immunoelectrophoretic identity of this macromolecule led to its designation by Schultze et al. 2 as β1B-glycoprotein. The name “hemopexin”, given by Grabar et al.,3 reflects the ability of the protein to bind heme† in an equimolar ratio.4,5 The other serum protein which binds metalloporphyrins, although with lower affinity,6 is albumin. In several of the following sections, the two proteins will be compared.