Iron

Iron is a chemical element in the periodic table that has the symbol Fe (L.: Ferrum) and atomic number 26. Iron is a group 8 and period 4 metal. Iron is notable for being the final element produced by stellar nucleosynthesis, and thus the heaviest element which does not require a supernova or similarly cataclysmic event for its formation. It is therefore the most abundant heavy metal in the universe.

Biological role

Iron is essential to all organisms, except for a few bacteria. It is mostly stably incorporated in the inside of metalloproteins, because in exposed or in free form it causes production of free radicals that are generally toxic to cells. To say that iron is free doesn't mean that it is free floating in the bodily fluids. Iron binds avidly to virtually all biomolecules so it will adhere nonspecifically to cell membranes, nucleic acids, proteins etc.

Related Topics:
Organism - Bacteria - Metalloprotein - Free radical - Cell membranes - Nucleic acids - Proteins

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Many animals incorporate iron into the heme complex, an essential component of cytochromes, which are proteins involved in redox reactions (including but not limited to respiration), and of oxygen carrying proteins hemoglobin and myoglobin. Inorganic iron involved in redox reactions is also found in the iron-sulfur clusters of many enzymes, such as nitrogenase (involved in the synthesis of ammonia from nitrogen and hydrogen) and hydrogenase. A class of non-heme iron proteins is responsible for a wide range of functions within several life forms, such as enzymes methane monooxygenase (oxidizes methane to methanol), ribonucleotide reductase (reduces ribose to deoxyribose; DNA biosynthesis), hemerythrins (oxygen transport and fixation in marine invertebrates) and purple acid phosphatase (hydrolysis of phosphate esters). When the body is fighting a bacterial infection, the body sequesters iron in the transporter protein transferrin so it cannot be used by bacteria.

Related Topics:
Heme - Cytochrome - Redox - Respiration - Hemoglobin - Myoglobin - Iron-sulfur cluster - Enzyme - Nitrogenase - Ammonia - Nitrogen - Hydrogen - Hydrogenase - Non-heme iron proteins - Enzymes - Methane monooxygenase - Methane - Methanol - Ribonucleotide reductase - Ribose - Deoxyribose - DNA biosynthesis - Hemerythrin - Oxygen - Marine invertebrate - Purple acid phosphatase - Hydrolysis - Phosphate - Ester - Infection - Transferrin

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Iron distribution is heavily regulated in mammals, partly as a defense against bacterial infection. The iron absorbed from the duodenum binds to transferrin, and is carried by blood to different cells. There it gets by an as yet unknown mechanism incorporated into target proteins. http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371%2Fjournal.pbio.0000079.

Related Topics:
Mammal - Duodenum - Blood - Cell

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Good sources of dietary iron include meat, fish, poultry, lentils, beans, leaf vegetables, tofu, chickpeas, black-eyed pea, strawberries and farina.

Related Topics:
Meat - Fish - Poultry - Lentil - Bean - Leaf vegetable - Tofu - Chickpea - Black-eyed pea - Strawberries - Farina

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Iron provided by dietary supplements is often found as Iron (II) fumarate. The RDA for iron varies considerably based on the age, gender, and source of dietary iron (heme-based iron has higher bioavailability)http://www.iom.edu/Object.File/Master/7/294/0.pdf. Also note the section below on precautions.

Related Topics:
Dietary supplement - Iron (II) fumarate - RDA - Heme - Bioavailability - Precautions

~ ~ ~ ~ ~ ~ ~ ~ ~ ~