Ferrochelatase

Ferrochelatase (FECH) catalyzes the last step in the formation of heme. FECH adds Fe+2 to protoporphyrin IX converting it to protoheme. The human FECH is a homodimer containing 2 similar domains and an iron-sulfur cluster. Defective FECH is the cause of porphyria.

Bacterial ferrochelatase turns human: Tyr13 determines the apparent metal specificity of Bacillus subtilis ferrochelatase ^[1]

Ferrochelatase produces . It can also . However, the ability to insert other . In this way Bacillus subtilis ferrochelatase can insert copper into protoporphyrin IX, but to a much less extent cobalt. In contrast, the human and Saccharomyces cerevisiae ferrochelatases prefer cobalt over copper. shows that , while A third residue, Tyr in B. subtilis, is a third ligand via a water molecule. Human and S. cerevisiae ferrochelatase utilizes In the structures of the ferrochelatases the Tyr/Met occupies the same position. We also know that the Tyr residue of the is a . By site directed mutagenesis and showed that the metal specificity changed so that the modified B. subtilis ferrochelatase . Two crystal structures are presented. how . The how a in the B. subtilis enzyme.