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Iron is both necessary to the body and potentially toxic. Controlling iron levels in the body is a critically important part of many aspects of human health and disease. Hematologists have been especially interested in systemic iron metabolism, because iron is essential for red blood cells, where most
The heme iron serves as a source or sink of electrons during electron transfer or redox chemistry. In peroxidase reactions, the porphyrin molecule also serves as an electron source, being able to delocalize radical electrons in the conjugated ring. In the transportation or detection of diatomic gases, the gas binds to the heme iron.
Absorption of dietary iron in iron salt form (as in most supplements) varies somewhat according to the body's need for iron, and is usually between 10% and 20% of iron intake. Absorption of iron from animal products, and some plant products, is in the form of heme iron, and is more efficient, allowing absorption of from 15% to 35% of intake.
Iron is a mineral that is crucial for optimal health and well-being. Found naturally in many foods and dietary supplements, it is a key component of hemoglobin, the part of red blood cells ...
The heme part is synthesized in a series of steps in the mitochondria and the cytosol of immature red blood cells, while the globin protein parts are synthesized by ribosomes in the cytosol. [41] Production of Hb continues in the cell throughout its early development from the proerythroblast to the reticulocyte in the bone marrow .
The most significant factor regulating iron uptake is the amount of iron present in the body. Iron absorption increases with sufficient iron storage and vice versa. Increased erythrocyte synthesis also stimulates iron absorption in the gut. [15] Therefore, oral bioavailability of iron varies greatly, ranging from less than 1% to greater than 50 ...
The heme consists of iron cation bound at the center of the conjugate base of the porphyrin, as well as other ligands attached to the "axial sites" of the iron. The porphyrin ring is a planar dianionic, tetradentate ligand. The iron is typically Fe 2+ or Fe 3+. One or two ligands are attached at the axial sites.
The human body has no controlled mechanism for excretion of iron. [23] This can lead to iron overload problems in patients treated with blood transfusions, as, for instance, with β-thalassemia. Iron is actually excreted in urine [24] and is also concentrated in bile [25] which is excreted in feces. [26]