Metabolism of manganese

Maneb or mancozeb. Studies show that maneb and mancozeb are metabolized to several compounds including ethylenethiourea (ETU), ethylene urea, and ethylenediamine (Jordan and Neal 1979 Lyman 1971) in plants and animals. ETU has been identified in the urine of occupationally-exposed sprayers of maneb and mancozeb (Kurttio and Savoleinen 1990 Kurttio et al. 1990). No studies were located concerning the metabolism of manganese originating from these fungicides in either humans or animals. 

Manganese in water may undergo oxidation at high pH or Eh (see Section 5.3.1.2) and is also subject to microbial activity. For example, Mn(II) in a lake was oxidized during the summer months, but this was inhibited by a microbial poison, indicating that the oxidation was mediated by bacteria (Johnston and Kipphut 1988). The microbial metabolism of manganese is presumed to be a function of pH, temperature, and other factors, but no data were located on this. 

Constantopoulos, G. (1970). Lipid metabolism of manganese-deficient algae. Plant Physiol. 45, 76-80. 

Metabolic Functions. Manganese is essential for normal body stmcture, reproduction, normal functioning of the central nervous system, and activation of numerous enzymes (126). Synthesis of the mucopolysaccharide chondroitin sulfate involves a series of reactions where manganese is required in at least five steps (127). These reactions are responsible for formation of polysaccharides and linkage between the polysaccharide and proteins that form... 

Nitrogen is normally supplied as an ammonium compound in dtric acid fermentations and suffident has to be supplied to enable the effect of manganese deficiency (increased levels of ammonium in the metabolic pool) to occur. Remember that increased metabolic pool ammonium has the effect of releasing the allosteric controls exerted on phosphofructokinase. 

Manganese and iron oxidation are coupled to cell growth and metabolism of organic carbon. Microbially deposited manganese oxide on stainless and mild steel alters electrochemical properties related to the potential for corrosion. Iron-oxidizing bacteria produce tubercles of iron oxides and hydroxides, creating oxygen-concentration cells that initiate a series of events that individually or collectively are very corrosive. 

We begin this overview of manganese biochemistry with a brief account of its role in the detoxification of free radicals, before considering the function of a dinuclear Mn(II) active site in the important eukaryotic urea cycle enzyme arginase. We then pass in review a few microbial Mn-containing enzymes involved in intermediary metabolism, and conclude with the very exciting recent results on the structure and function of the catalytic manganese cluster involved in the photosynthetic oxidation of water. 

An enzyme cofactor can be either an inorganic ion (usually a metal cation) or a small organic molecule called a coenzyme. In fact, the requirement of many enzymes for metal-ion cofactors is the main reason behind our dietary need for trace minerals. Iron, zinc, copper, manganese, molybdenum, cobalt, nickel, and selenium are all essential trace elements that function as enzyme cofactors. A large number of different organic molecules also serve as coenzymes. Often, although not always, the coenzyme is a vitamin. Thiamine (vitamin Bj), for example, is a coenzyme required in the metabolism of carbohydrates. 

Rapid development of this area followed the discovery of routes to these complexes, either by ready conversion of terminal alkynes to vinylidene complexes in reactions with manganese, rhenium, and the iron-group metal complexes (11-14) or by protonation or alkylation of some metal Recent work has demonstrated the importance of vinylidene complexes in the metabolism of some chlorinated hydrocarbons (DDT) using iron porphyrin-based enzymes (15). Interconversions of alkyne and vinylidene ligands occur readily on multimetal centers. Several reactions involving organometallic reagents may proceed via intermediate vinylidene complexes. 

Mertz DP, Koschnick R, Wilk G, et al. 1968. [Studies on the metabolism of trace elements in humans. I. Serum values for cobalt, nickel, silver, cadmium, chromium, molybdenum, manganese],... 

Stone, A. T. (1987a). Microbial metabolates and the reductive dissolution of manganese oxides Oxalate and pyruvate. Geochim. Cosmochim. Acta 51, 919-925. 

In plant cells, a peroxidase activity showed to be correlated with the ability of plant cultures to metabolize PCBs. Nevertheless, as mentioned above in fungal cultures, no correlation of manganese- and lignin-peroxidase activities with PCB degradation was found [131]. 

Calhoun, B. A., J. Overmeyer, and W. Sunderman Jr. Studies of trace metal metabolism Electron paramagnetic resonance of manganese in ribonucleic acids. Proc. Soc. Exptl. Biol. Med. 119, 1089 (1965). 

Ions are present dissolved in various fluids of the body, and some are present in very small quantities. Discuss the importance to human metabolism of small quantities of the following zinc, manganese, cobalt and iron. 

Manganese has been found to be an essential nutrient for the human as well as for many other living organisms however, in excessive amounts, it is also a toxic material (1-6). Deficiency symptoms for manganese in several species have been created and manganese metabolic roles have, at least in part, been defined (5,7-15). So called "normal" manganese concentrations in blood have been established (1,10,16). Kinetics of manganese uptake and metabolism by... 

Because of the blood lowering cholesterol effects of a manganese deficiency, involvement of manganese in lipid metabolism has been a topic of research interest as reviewed by Johnson and Kies in this volume. 

The essentiality of manganese (Mn) for animals was established in 1931 by Orent and McCollum (3) and Kemmerer and co-workers (4j who demonstrated poor growth in mice and abnormal reproduction in rats fed diets deficient in the element. Today it is known that under rigidly controlled laboratory conditions, Mn deficiency results in a wide variety of structural and metabolic defects. 

STRAUSE AND SALTMAN Role of Manganese in Bone Metabolism... 

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