Molybdenum biological

O. Akopajan, Some Biological Shifts in the Bodies of Workers in Contact with Molybdenum Dust, Second Scientific Conference of the Institute of Labor of Hygiene and Occupational Diseases on Problems of Labor Hygiene and Occupational Pathology, Erevan, 1963, pp. 103—106. 

The clearest manifestation of molybdenum in biology is its presence in over 20 enzymes which participate in a wide variety of redox processes (44—46). Some of the Mo enzymes and their occurrence are as follows ... 

R. Eisler, Molybdenum Ha rds to Fish, Wildlife, and Invertebrates M Synoptic Keview, U.S. Fish and Wildlife Service Biology Report No. 85 (1.19), 1989,... 

About 50% of copper in food is absorbed, usually under equitibrium conditions, and stored in the tiver and muscles. Excretion is mainly via the bile, and only a few percent of the absorbed amount is found in urine. The excretion of copper from the human body is influenced by molybdenum. A low molybdenum concentration in the diet causes a low excretion of copper, and a high intake results in a considerable increase in copper excretion (68). This copper—molybdenum relationship appears to correlate with copper deficiency symptoms in cattle. It has been suggested that, at the pH of the intestine, copper and molybdate ions react to form biologically unavailable copper molybdate (69). 

Molybdenum because of its unique chemical versatility and unusually high bio-availability has been incorporated widely into biological systems. It is the only second-row transition metal that is essential for most of living organisms and belongs to elements (along with Cu, Cd, Hg, Pb and Cr) potentially hazardous to humans. 

Bi-functional radio-analytical scheme, based on exchange and extraction column chromatography, which provides the reliable information on molybdenum and uranium contents in biological materials has been elaborated. The contribution of uranium fission reaction has been strictly monitored. The uncertainty of the results of Mo determination by the presented method is very low. 

Finally, in 1797, the Frenchman L. N. Vauquelin discovered the oxide of a new element in a Siberian mineral, now known as crocoite (PbCr04), and in the following year isolated the metal itself by charcoal reduction. This was subsequently named chromium (Greek xpco ia, chroma, colour) because of the variety of colours found in its compounds. Since their discoveries the metals and their compounds have become vitally important in many industries and, as one of the biologically active transition elements, molybdenum has been the subject of a great deal of attention in recent years, especially in the field of nitrogen fixation (p. 1035). 

It appears that chromium(III) is an essential trace element in mammalian metabolism and, together with insulin, is responsible for the clearance of glucose from the blood-stream. Tungsten too has been found to have a role in some enzymes converting CO2 into formic acid but, from the point of view of biological activity, the focus of interest in this group is unquestionably on molybdenum. 

Hille, R. Massey, V. Molybdenum Enzymes—MetM Ions in Biology Wiley Interscience New York, 1985 Vol. 7. 

We tend to think of metals as lustrous solids copper, tin, gold, silver, iron. We are less likely to think of individual metal atoms in biological machines. Nevertheless, plants and animals require the presence of tiny amounts of transition metals. Humans require most of the elements in the first transition metal series and at least one element from the second transition metal series, molybdenum. 

Hille R (2002) Molybdenum and tungsten in biology. Trends in Biochem Sci 27 360-367. 

Holm, R.H. (1990). The biological relevant oxygen atom transfer of molybdenum. Coordin. Chem. 

---