Copper in Living Organisms

Before they were characterized by x-ray crystallography, the classification of the structures of copper proteins was initially based on the spectroscopic features of their active site in the oxidized state. The tremendous development of crystallographic and spectroscopic techniques in recent years has enabled the identification of as many as seven different types of active sites in these proteins type 1, type 2, type 3, type 4, CuA, CuB and Cuz. The characteristics of these metal sites are briefly described below. 

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Cadmium occurs naturally as sulfide co-deposited with zinc, copper, and lead sulfides. It is produced as a by-product in above-mentioned metal processing. Similar to lead and mercury, this heavy metal has no known biological functions in living organisms, and accordingly its accumulation in food and water leads to undesirable consequences to biota. Cadmium toxicology is related to dangerous influence to CNS and excretion systems, firstly, on kidney. 

BIOINORGANIC CHEMISTRY. Study of the mechanisms involved in the behavior of metal-containing molecules in living organisms, e.g., biological transport of iron, the effect of copper on nucleic acid and iiucleupruleins, molybdenum, and manganese complexes, etc. 

In addition to being important in industry, transition metal ions play a vital role in living organisms. For example, complexes of iron provide for the transport and storage of oxygen, molybdenum and iron compounds are catalysts in nitrogen fixation, zinc is found in more than 150 biomolecules in humans, copper and iron play a crucial role in the respiratory cycle, and cobalt is found in essential biomolecules such as vitamin Bi2-... 

In spite of the long history of association between copper and man, the fact that copper is present in living organisms did not become known until 150 years ago, when copper was found in plants (B31, M18) and soon after... 

It seems evident from all this that in living organisms, including man, elaborate physiological mechanisms must function to ensure that copper is made available in sufficient amount and in the right form whenever and wherever it is needed and, at the same time, that accumulation of toxic amounts is prevented. 

An example of an oxidation-reduction reaction is the one that occurs when a strip of metallic zinc is placed in an aqueous solution containing copper ions. Although both zinc and copper ions play roles in life processes, this particular reaction does not occur in living organisms. However, it is a good place to start our discussion of electron transfer because, in this comparatively simple reaction, it is fairly easy to follow where the electrons are going. (It is not always quite as easy to keep track of the details in biological redox reactions.) The experimental observation is that the zinc metal disappears and zinc ions go into solution, while copper ions are removed from the solution and copper metal is deposited. The equation for this reaction is... 

However, it should be kept in mind, that these reactions are dependent on the equilibrium constants and thus, on the respective concentrations of either ligands. The coordinated copper is known to remain kinetically labile even in naturally occuring Cu-proteins. Although it may be below the usual detection limit, it could not be excluded, that a pool of low copper complexes do exist in living organisms. 

Copper (II), Bismuth (III) and lead (II), ai e important elements in the environment and they have essential roles in different biologieal systems. Lead is widely distributed in nature and exhibits severe deleterious effeets on human [1]. Copper is an essential element for the normal metabolism of many living organisms. Bismuth has been used in medieines for the treatment of helieobaeter pylorie-indueed gastritis [2, 3]. Therefore traee analysis of these elements is important for monitoring their eoneentration in the environment. 

Copper is an essential trace metal for all living beings. However, although copper is indispensable for many physiological functions of human organism, the presence of excess amount of copper in the body may be toxic. One possible source of copper in human body that is scarcely investigated is dental materials. 

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