Non-heme iron protein

In biochemistry, non-heme iron proteins describe families of enzymes that utilize iron at the active site but lack heme cofactors. Iron-sulfur proteins, including those that are enzymes, are not included in this definition.

Some non-heme iron proteins contain one Fe at their active sites, others have pairs of Fe centers:

• Many mono-Fe proteins are alpha-ketoglutarate-dependent hydroxylases. Major examples are the lipoxygenases, isopenicillin N synthase, protocatechuate 3,4-dioxygenase, deacetoxycephalosporin-C synthase,^[1] and aromatic amino acid hydroxylases.^[2]

Illustrative transformation catalyzed by a non-heme iron protein.

• Major diiron enzymes include hemerythrin, some ribonucleotide reductases,^[3] some methane monooxygenases, purple acid phosphatases, and ferritin.^[4][5]

Oxygenation of hemerythrin, a non-heme diiron protein.

See also

• Iron-binding proteins