Molybdenum

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Molybdenum (chemical symbol Mo) is one of the essential trace elements. Its biological role is as a part of a molybdenum cofactor, essential for the functioning of several important metabolic enzymes.

Chemistry

Basic chemistry

Molybdenum has the atomic number 42, with an atomic weight of 95.94 g/mol. It is a transition metal with a silvery-white colouration ².

Radiochemistry

35 isotopes of molybdenum are known, of these 7 are stable and 28 unstable, i.e. radioactive. Although it is thought that there may be as many as 30 isotopes still to be discovered ⁴.

Diet, absorption, transport and storage

pending

Biological function

Molybdenum is essential for the normal functioning of four enzymes (molybdoenzymes) in humans:

sulfite oxidase
- oxidation of sulfite to sulfate, the terminal reaction in the oxidation of S-containing amino acids
xanthine oxidase
- catalyses hypoxanthine to xanthine, and xanthine to uric acid, important in the purine degradation pathway
aldehyde oxidase
- key for hepatic drug metabolism
mitochondrial amidoxime-reducing component (mARC)
- reduction of some N-hydroxylated substrates ¹

Deficiency

Very rare, a few isolated case reports, mainly in those on total parenteral nutrition ³.

Toxicity

No toxicity has been reported in humans from excessive intake of molybdenum ⁵.

Radiological importance

molybdenum metal is a key component of the anodes in some x-ray tubes, especially in mammography
molybdenum generators are important as a source for Tc-99m

History and etymology

Molybdenum was discovered by Karl Scheele, a Swedish chemist, in 1778. He originally thought it was lead, thus the element was named for the Ancient Greek word molybdos, meaning "lead-like" ¹.

~~-<p><strong>Molybdenum</strong> (chemical symbol <strong>Mo</strong>) is one of the <a title="Trace elements" href="/articles/trace-elements">trace elements</a>.</p>~~
+<p><strong>Molybdenum</strong> (chemical symbol <strong>Mo</strong>) is one of the essential <a href="/articles/trace-elements">trace elements</a>. Its biological role is as a part of a <strong>molybdenum cofactor</strong>, essential for the functioning of several important metabolic enzymes. </p><h4>Chemistry</h4><h5>Basic chemistry</h5><p>Molybdenum has the atomic number 42, with an atomic weight of 95.94 g/mol. It is a transition metal with a silvery-white colouration <sup>2</sup>. </p><h5>Radiochemistry</h5><p>35 isotopes of molybdenum are known, of these 7 are stable and 28 unstable, i.e. radioactive. Although it is thought that there may be as many as 30 isotopes still to be discovered <sup>4</sup>. </p><h4>Diet, absorption, transport and storage</h4><p><em>pending</em></p><h4>Biological function</h4><p>Molybdenum is essential for the normal functioning of four enzymes (molybdoenzymes) in humans:</p><ul>
+<li>sulfite oxidase<ul><li>oxidation of sulfite to sulfate, the terminal reaction in the oxidation of S-containing <a href="/articles/amino-acids-1">amino acids</a>
+</li></ul>
+</li>
+<li>xanthine oxidase<ul><li>catalyses hypoxanthine to xanthine, and xanthine to uric acid, important in the purine degradation pathway</li></ul>
+</li>
+<li>aldehyde oxidase<ul><li>key for hepatic drug metabolism</li></ul>
+</li>
+<li>mitochondrial amidoxime-reducing component (mARC)<ul><li>reduction of some N-hydroxylated substrates <sup>1</sup>
+</li></ul>
+</li>
+</ul><h4>Deficiency</h4><p>Very rare, a few isolated case reports, mainly in those on total parenteral nutrition <sup>3</sup>.</p><h4>Toxicity</h4><p>No toxicity has been reported in humans from excessive intake of molybdenum <sup>5</sup>. </p><h4>Radiological importance</h4><ul>
+<li>molybdenum metal is a key component of the <a href="/articles/anode-1">anodes</a> in some <a href="/articles/x-ray-tube-1">x-ray tubes</a>, especially in <a href="/articles/mammography">mammography</a>
+</li>
+<li>molybdenum generators are important as a source for <a href="/articles/tc-99m">Tc-99m</a>
+</li>
+</ul><h4>History and etymology</h4><p>Molybdenum was discovered by <strong>Karl Scheele</strong>, a Swedish chemist, in 1778. He originally thought it was lead, thus the element was named for the Ancient Greek word molybdos, meaning "lead-like" <sup>1</sup>.</p>

References changed:

1. Novotny JA, Peterson CA. Molybdenum. (2018) Advances in nutrition (Bethesda, Md.). 9 (3): 272-273. <a href="https://doi.org/10.1093/advances/nmx001">doi:10.1093/advances/nmx001</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/29767695">Pubmed</a> <span class="ref_v4"></span>
1. Novotny JA, Peterson CA. Molybdenum. (2018) Advances in nutrition (Bethesda, Md.). 9 (3): 272-273. <a href="https://doi.org/10.1093/advances/nmx001">doi:10.1093/advances/nmx001</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/29767695">Pubmed</a> <span class="ref_v4"></span>
2. William Alexander Newman Dorland. Dorland's Illustrated Medical Dictionary. (2018) <a href="https://books.google.co.uk/books?vid=ISBN9781416023647">ISBN: 9781416023647</a><span class="ref_v4"></span>
2. William Alexander Newman Dorland. Dorland's Illustrated Medical Dictionary. (2018) <a href="https://books.google.co.uk/books?vid=ISBN9781416023647">ISBN: 9781416023647</a><span class="ref_v4"></span>
3. Stehle P, Stoffel-Wagner B, Kuhn KS. Parenteral trace element provision: recent clinical research and practical conclusions. (2016) European journal of clinical nutrition. 70 (8): 886-93. <a href="https://doi.org/10.1038/ejcn.2016.53">doi:10.1038/ejcn.2016.53</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/27049031">Pubmed</a> <span class="ref_v4"></span>
4. Parker AM and Thoennessen M. Discovery of Rubidium, Strontium, Molybdenum, and Rhodium Isotopes. (2012) Atom.Data Nucl.Data Tabl. 98 (2012) 812-831. DOI: 10.1016/j.adt.2012.06.001.
4. Parker AM and Thoennessen M. Discovery of Rubidium, Strontium, Molybdenum, and Rhodium Isotopes. (2012) Atom.Data Nucl.Data Tabl. 98 (2012) 812-831. DOI: 10.1016/j.adt.2012.06.001.
5. Institute of Medicine (US) Panel on Micronutrients. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington (DC): National Academies Press (US); 2001. 11, Molybdenum. Available from: https://www.ncbi.nlm.nih.gov/books/NBK222301/
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