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The manganese cycle is the biogeochemical cycle of manganese through the atmosphere, hydrosphere, biosphere and lithosphere. There are bacteria that oxidise manganese to insoluble oxides, and others that reduce it to Mn 2+ in order to use it.
Manganese is an essential human dietary element and is present as a coenzyme in several biological processes, which include macronutrient metabolism, bone formation, and free radical defense systems. 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.
Manganese is also important in photosynthetic oxygen evolution in chloroplasts in plants. The oxygen-evolving complex (OEC) is a part of photosystem II contained in the thylakoid membranes of chloroplasts; it is responsible for the terminal photooxidation of water during the light reactions of photosynthesis , and has a metalloenzyme core ...
The Kok cycle. The oxidation state of the manganese centres is subject to debate. [1] X-ray crystal structure of the Mn 4 O 5 Ca core of the oxygen evolving complex of Photosystem II at a resolution of 1.9 Å. [2]
Manganese cycle; Manganism; Mercury-manganese star; P. Manganese production by country; S. Spiegeleisen This page was last edited on 3 October 2017, at 22:13 ...
The oxygen-evolving complex is the site of water oxidation. It is a metallo-oxo cluster comprising four manganese ions (in oxidation states ranging from +3 to +4) [6] and one divalent calcium ion. When it oxidizes water, producing oxygen gas and protons, it sequentially delivers the four electrons from water to a tyrosine (D1-Y161) sidechain ...
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The Mn(II) formed is soluble in most electrolytes and its dissolution degrades the cathode. With this in mind many manganese cathodes are substituted or doped to keep the average manganese oxidation state above +3.5 during battery use or they will suffer from lower overall capacities as a function of cycle life and temperature. [6]