Furthermore, heme B is found in cytochrome b, a key component in Q-cytochrome c oxidoreductase (complex III) in oxidative phosphorylation.

The interior of the active site pocket contains a highly conserved acidic surface that facilitates proton extraction from protoporphyrin.

Histidine and aspartate residues roughly 20 angstroms from the center of the active site on the mitochondrial matrix side of the enzyme coordinate metal binding.

A highly conserved histidine residue (His183 in B. subtilis, His263 in humans) is essential for determining the type of distortion, as well as acting as the initial proton acceptor from protoporphyrin.

[9] The disease can result from a variety of mutations in FECH, most of which behave in an autosomal dominant manner with low clinical penetrance.

Clinically, patients with EPP present with a range of symptoms, from asymptomatic to suffering from an extremely painful photosensitivity.

[11] Ferrochelatase interacts with numerous other enzymes involved in heme biosynthesis, catabolism, and transport, including protoporphyrinogen oxidase, 5-aminolevulinate synthase, ABCB10, ABCB7, succinyl-CoA synthetase,[12] and mitoferrin-1.

[13] Multiple studies have suggested the existence of an oligomeric complex that enables substrate channeling and coordination of overall iron and porphyrin metabolism throughout the cell.