Iron-dependent enzymes

Iron-dependent enzymes are proteins that require iron as a cofactor to catalyze diverse biochemical reactions essential for life. They are prevalent across all kingdoms of life, constituting approximately 6.5% of all human enzymes and about 2% of human genes encoding iron-proteins. They are classified into three main structural types based on their active sites: non-heme mono-iron enzymes (containing individual iron ions), heme-containing iron enzymes (iron within a heme group), and iron-sulfur cluster enzymes (containing iron-sulfur clusters). Functionally, they are often oxidoreductases, including dioxygenases and monooxygenases, and specific classes like α-ketoglutarate/iron-dependent dioxygenases and multinuclear non-heme iron dependent oxidative enzymes (MNIOs). These enzymes play crucial roles in processes like oxygen metabolism, post-translational modifications, and the modification of various cellular molecules. Their cellular distribution is widespread, with a notable presence in the endoplasmic reticulum. Intracellular iron levels are tightly regulated by systems like the IRP/IRE system to prevent the detrimental effects of both iron deficiency and overload, highlighting the critical importance of these enzymes in maintaining cellular and systemic health.