Iron mobilization and incorporation into heme

Iron mobilization and incorporation into heme is a multi-step biological process essential for the production of hemoproteins such as hemoglobin, myoglobin, and cytochromes [StatPearls, 2023]. The process begins with the mobilization of iron from intracellular stores like ferritin or extracellular transport via transferrin, followed by its delivery to the mitochondrial matrix [NIH, 2022]. The final and rate-limiting step of heme biosynthesis is the incorporation of ferrous iron (Fe2+) into the protoporphyrin IX ring, a reaction catalyzed by the mitochondrial enzyme ferrochelatase (FECH) [UniProt P22392]. This pathway is tightly regulated to maintain iron homeostasis and prevent the accumulation of toxic free iron or porphyrin intermediates [PubMed PMID: 21865125]. Clinical disorders associated with this process include iron-deficiency anemia, where iron is scarce, and various porphyrias, which result from enzymatic defects in the heme synthesis chain [StatPearls, 2023]. Therapeutic strategies often involve iron supplementation with agents like ferrous sulfate, iron chelation therapy using deferoxamine to treat overload, or the management of environmental inhibitors like lead [PubChem, 2024]. Proper functioning of this pathway is critical for erythropoiesis and cellular respiration across all aerobic organisms [NIH, 2022].

Other names

Heme biosynthesis pathwayIron-heme metabolismProtoporphyrin IX iron-complex metabolic processHeme synthesis pathway

The pathway is modulated by providing iron substrates (e.g., ferrous sulfate), removing excess iron via chelation (e.g., deferoxamine), or through the inhibition of key enzymes like ferrochelatase by heavy metals such as lead [StatPearls, 2023; PubChem, 2024].