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Manganese is an essential human dietary element. It is present as a coenzyme in several biological processes, which include macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. [3] The human body contains about 12 mg of manganese, mostly in the bones.
Manganese precipitates in soils in the form of manganese-iron oxide minerals, which promote nutrient and organic matter accumulation due to their high surface area. Manganese is the tenth most abundant metal in the Earth's crust, making up approximately 0.1% of the total composition, or about 0.019 mol kg −1, which is found mostly in the ...
Because of zinc's antibiotic nature, it is often used in many drugs against bacterial infections in humans. Inversely, due to the bacterial nature of mitochondria, zinc antibiotics are also lethal to mitochondria and results in cell death at high concentrations. [8] Zinc is also used in a number of transcription factors, proteins and enzymes.
Manganese is a critical component in dozens of proteins and enzymes. [8] The human body contains about 12 mg of manganese, mostly in the bones. The soft tissue remainder is concentrated in the liver and kidneys. [9] In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes. [101]
Manganese – Nearly all mitochondria, and many bacteria, contain a form with manganese (Mn-SOD): For example, the Mn-SOD found in human mitochondria. The ligands of the manganese ions are 3 histidine side-chains, an aspartate side-chain and a water molecule or hydroxy ligand, depending on the Mn oxidation state (respectively II and III). [12]
In 2007 his team showed that high intracellular levels of manganese(II) in D. radiodurans protect proteins from being oxidized by radiation, and they proposed the idea that "protein, rather than DNA, is the principal target of the biological action of [ionizing radiation] in sensitive bacteria, and extreme resistance in Mn-accumulating bacteria ...
In human SOD, the active metal is copper, as Cu(II) or Cu(I), coordinated tetrahedrally by four histidine residues. This enzyme also contains zinc ions for stabilization and is activated by copper chaperone for superoxide dismutase . Other isozymes may contain iron, manganese or nickel. The activity of Ni-SOD involves nickel(III), an unusual ...
Mammalian arginase is active as a trimer, but some bacterial arginases are hexameric. [3] The enzyme requires a two-molecule metal cluster of manganese in order to maintain proper function. These Mn 2+ ions coordinate with water, orienting and stabilizing the molecule and allowing water to act as a nucleophile and attack L-arginine, hydrolyzing ...