Manganese biological significance

F. C. Wedler, Biological significance of manganese in mammalian systems, Prog. Med. Chem., 30 (1993), 89-133. 

All synthesis of amide bonds of biological significance are dependent upon energy, commonly in the form of ATP and of magnesium or manganese ions as cofactor. Some syntheses of amide bonds take place without the presence of any known coenzyme and others are dependent upon coenzyme A (CoA). The synthesis of acetyl sulfanilamide from acetate and sulfanilamide is an amide bond synthesis dependent upon CoA. This conjugation reaction has been studied by Chou and lipmann (1952) who showed that two enzymes took part in the reaction and that acetyl-l.S CoA was an intermediate product. 

The rates of Mn(II) removal in some natural waters are similar to the Mn(II) oxidation rates predicted on the basis of these laboratory studies. However, in other cases the rate of manganese removal in natural waters is much faster than that expected on the basis of this work. In these systems significant manganese removal may occur as the result of adsorption, bacterially mediated oxidation, or biological uptake. 

Biological, chemical, and physical effects of airborne metals are a direct function of particle size, concentration, and composition. The major parameter governing the significance of natural and anthropogenic emissions of environmentally important metals is particle size. Metals associated with fine particulates are of concern particles larger than about 3-fjim aerodynamic equivalent diameter are minimally respirable, are ineffective in atmospheric interactions, and have a short air residence time. Seventeen environmentally important metals are identified arsenic, beryllium, cadmium, chromium, copper, iron, mercury, magnesium, manganese, nickel, lead, antimony, selenium, tin, vanadium, and zinc. This report reviews the major sources of these metals with emphasis on fine particulate emissions. 

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