Search results
Results from the WOW.Com Content Network
Molybdenum deficiency has also been reported as a consequence of non-molybdenum supplemented total parenteral nutrition (complete intravenous feeding) for long periods of time. It results in high blood levels of sulfite and urate, in much the same way as molybdenum cofactor deficiency. Since pure molybdenum deficiency from this cause occurs ...
O-donors [definition needed] such as HPO 2− 4 were abundant in the prebiotic atmosphere. [6] Metal ion binding to such O-donors was required to build the biological polymers, since the bond is generally weak, it can catalyze the required reaction and dissociate after (i.e. Mg 2+ in DNA synthesis).
Most nitrogenases contain an iron–molybdenum cofactor FeMoco, which is believed to contain either Mo(III) or Mo(IV). [14] [15] By contrast Mo(VI) and Mo(IV) are complexed with molybdopterin in all other molybdenum-bearing enzymes. [16] Molybdenum is an essential element for all higher eukaryote organisms, including humans.
Nonmetals show more variability in their properties than do metals. [1] Metalloids are included here since they behave predominately as chemically weak nonmetals.. Physically, they nearly all exist as diatomic or monatomic gases, or polyatomic solids having more substantial (open-packed) forms and relatively small atomic radii, unlike metals, which are nearly all solid and close-packed, and ...
Metal ions in biology were studied in various specializations. In nutrition, it was to define the essentials for life; in toxicology, to define how the adverse effects of certain metal ions in biological systems and in pharmacology for their therapeutic effects. [2] In each field, at first, they were studied and separated on a basis of ...
The halides of low-valent early metals often are clusters with extensive M-M bonding. The situation contrasts with the higher halides of these metals and virtually all halides of the late transition metals, where metal-halide bonding is replete. Transition metal halide clusters are prevalent for the heavier metals: Zr, Hf, Nb, Ta, Mo, W, and Re.
Bioinorganic chemistry is a field that examines the role of metals in biology.Bioinorganic chemistry includes the study of both natural phenomena such as the behavior of metalloproteins as well as artificially introduced metals, including those that are non-essential, in medicine and toxicology.
The remaining elements found in living things are primarily metals that play a role in determining protein structure. Examples include iron, essential to hemoglobin; and magnesium, essential to chlorophyll. Some elements are essential only to certain taxonomic groups of organisms, particularly the prokaryotes.