| Popis: |
Heme, an iron-porphyrin complex, is the prosthetic group of hemoglobin, myoglobin, cytochromes, and many other proteins. Iron is required for the biosynthesis of heme and other non-heme iron containing proteins. Several specific proteins participate in the orchestration of iron metabolism. Iron metabolism consists of the absorption of dietary iron from the gastrointestinal tract, transport in the blood, storage in the liver and macrophages, and utilization in the cells requiring synthesis of iron-containing proteins. Iron deficiency causes anemia and iron excess causes iron accumulation diseases known as hemochromatosis. Ferrous iron is absorbed principally from the mature enterocytes lining the absorptive villi of the duodenum. At the apical membrane of the enterocyte, Fe 3+ is converted to Fe 2+ by ferrireductase followed by its uptake mediated by divalent transporter 1 (DMT1). The internalized Fe 2+ is either temporarily stored after conversion to Fe 3+ as ferritin, or transported across the cell for transport to the portal capillary blood circulation |
