Biological systems transition metals

In a perspective provided by structure of the Periodic Table, molybdenum and tungsten are distinct in being the only 4d- and 5d-transition metals that are required for the normal metabolism of biological systems. These metals play a vital role as the catalytic centres of a wide variety of enzymes. Mo was first identified as an essential trace element in the 1930s, because of its role in nitrogen fixation this metal is now known to be the catalytic centre of over 50 enzymes. Evidence for the involvement of W in biological systems has been obtained only relatively recently, especially for enzymes of hyperthermophilic archea that thrive near lOOX. ... 

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. 

The electron transfer rates in biological systems differ from those between small transition metal complexes in solution because the electron transfer is generally long-range, often greater than 10 A [1]. For long-range transfer (the nonadiabatic limit), the rate constant is... 

Interactions of histidine and other imidazole derivatives with transition metal ions in chemical and biological systems. R. J. Sundberg and R. B. Martin, Chem. Rev., 1974, 74, 471-517 (517). 

Isoxazoles are privileged aromatic heterocycles due to their wide spectrum of biological activities and their use as versatile building blocks in organic synthesis. Recent progress in the field of transition-metal-catalyzed cross-coupling reactions on isoxazole systems has been summarized and discussed <06EJO3283>. 

Metal complexes, especially involving transition metals, are known for their role as catalysts in a broad variety of chemical processes including isomerization, oxidization, hydrogenation, and polymerization. Such catalytic reactions play an important role not only in many industrial processes, such as petroleum and polymer industries, but also in many biological systems, e.g., a variety of selective oxidation catalysts with heme (1) and nonheme (2) iron centers. The transition metals in these systems usually constitute a fundamental part of the catalyst, due to their... 

Tables 1.2-1.6 list some of the important geometries assumed by metal ions in biological systems. Common geometries adopted by transition metal ions that will...

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