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Heme is an iron- containing compound found in a number of biologically important molecules. Hemoglobin and heme containing proteins that are involved in the transport and storage of oxygen. Hemoglobin is the primary protein found in red blood cells and represents about two thirds of the body's iron. Myoglobin functions in the transport and short- term storage of oxygen in muscle cells, helping to match the supply of oxygen to the demand of working muscles.
In cases that oxygen is not enough (hypoxia), such as that experienced by these who live at high altitudes or these with chronic lung disease, induces compensatory physiologic responses including increased red blood cell formation, increased blood vessels growth (angiogenesis) and increased production of enzymes utilizes in anaerobic metabolism. In all the above mentioned processes iron has a vital role.
Cytochromes are heme containing compounds that are critical to cellular energy production and therefore, life, through their roles in mitochondrial electron transport. Nonheme – iron containing enzymes, such as NADH dehydregenase and succinate dehydrogenase are also critical to energy metabolism.
Cytochrome p-450 is a family of enzymes that functions in the metabolism of a number of important biological molecules, as well as the detoxification and metabolism of drugs and pollutants.
Catalase and peroxidases are heme- containing enzymes that protect cells against the accumulation of hydrogen peroxide. As part of the immune response, some white blood cells engulf bacteria and expose them to Ros (reactive oxygen species) in order to kill them. The synthesis of one such Ros, hypocholorous acid, by neutrophils is catalyzed by the heme- containing enzyme eloperexidase.
Other important enzyme that is iron- dependent is Ribonucleotide reductase that is required for DNA synthesis. Thus iron is required for a number of vital functions, including growth, reproduction, healing and immune function.
Iron deficiency anemia in early life is related to altered behavioral and neural development. Studies in human infants suggest that this is an irreversible effect that may be related to changes in chemistry of neurotransmitters, organization and morphology of neuronal networks, and neurobiology of myelination.
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