Serum heme-albumin: an allosteric protein.

Heme scavenging by plasma proteins, including serum albumin (SA), provides protection against free-heme oxidative damage, limits access by pathogens to the heme, and contributes to iron homeostasis by recycling the heme iron. In turn, serum heme-albumin (SA-heme) acquires heme-based ligand-binding and (pseudo-)enzymatic properties. Heme binding to SA and SA-heme reactivity are allosterically and competitively modulated by endogenous and exogenous third components, this being relevant in pharmacotherapy management.