Non-heme iron protein
From Wikipedia, the free encyclopedia
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. By tradition, non-heme iron enzymes refers to those involved in oxygen activation,[1] such as those described below.
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,[2] and aromatic amino acid hydroxylases.[3][4]
- Diiron enzymes include hemerythrin, some ribonucleotide reductases,[5] and some methane monooxygenases,[6] Some of these active sites are mixed valence (Fe(II)Fe(III)) and some are diferrous (Fe(II)Fe(II)).[7]
Oxygenation of hemerythrin, a non-heme diiron protein.