The 42nd annual Christmas Chemistry Lecture given by Professor Bassam Shakashiri on December 10th and 11th celebrates the chemistry of element #42, molybdenum.
December 10 and 11, 2011, of this year mark the 42nd annual Christmas Chemistry lecture given by Bassam Shakashiri of the University of Wisconsin-Madison, who is currently President-Elect of the American Chemical Society. Since the lecture number has traditionally corresponded to the selection of the element to discuss, this year’s topic is molybdenum, which happens to have an interesting role in biology.
When considering the elements that are the fundamental building blocks of life, biology abounds with the lighter elements such as carbon, nitrogen, oxygen, and hydrogen. Metals are found sparingly, but they often play critical roles that cannot be accomplished by one of the more common elements.
Even among biological metals, however, molybdenum is unexpected because it is considerably heavier than zinc, the next heaviest biologically important element. In numerous bacteria, molybdenum is featured in the active site of enzymes that carry out the process of nitrogen fixation, the high energy process of converting nitrogen from the atmosphere into a biologically usable form. Few organisms have the ability to harvest atmospheric nitrogen; humans, animals, and most plants all must consume compounds of nitrogen premade by other organisms to access this element, which makes molybdenum an essential element in supporting the food web.
Instead of fixing nitrogen, humans use molybdenum for the oxidation of several small molecules as part of the carbon, nitrogen, and sulfur element cycles. Molybdenum is part of a diet that includes eggs, green beans, cereal grains, cucumbers, and sunflower seeds. Insufficient dietary supply of molybdenum has been implicated in higher levels of esophageal cancer, but deficiencies are rare and only tend to occur in geographic regions in which the soil is naturally poor in the element. Molybdenum is also found in tooth enamel and helps prevent tooth decay.
More information about the health effects of molybdenum can be found at http://www.cancer.org/Treatment/TreatmentsandSideEffects/ComplementaryandAlternativeMedicine/HerbsVitaminsandMinerals/molybdenum