| Copper scavenges superoxide and other reactive oxygen species
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| Copper is associated with several oxygenase enzymes. These include cytochrome oxidase and superoxide dismutase, the
latter also requiring zinc for activity. One of the main roles of copper, especially in superoxide dismutase, but also in association with the plasma copper-carrying protein ceruloplasmin, is the scavenging of superoxide and other reactive oxygen species. Copper is also required for the crosslinking of collagen, being an essential component of lysyl oxidase.
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| Absorption of copper from the gut is associated with metallothioneine. Copper availability in the diet is less affected by dietary constituents than zinc, although high fiber intake reduces availability by complexing with copper.
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| Rare copper deficiency produces an anemia; skin and hair may also be affected. Copper deficiency is most likely to occur from reduced intake or excess loss, e.g. during renal dialysis. Deficiency manifests itself as a microcytic hypochromic (pale erythrocytes) anemia that is resistant to iron therapy. There is also a reduction in the number of leukocytes in the blood (neutropenia) and degeneration of vascular tissue with bleeding (due to defects in elastin and collagen production). Skin depigmentation and alteration in hair structure also occur in severe deficiency.
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| Copper excess causes liver cirrhosis
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| When taken orally, copper is generally nontoxic but in large doses it accumulates in tissues and can interfere with other metal ions such as iron and zinc. Chronic excessive intake, however, results in liver cirrhosis. Acute toxicity is manifested by marked hemolysis and damage to both liver and brain cells. The latter is seen in the inherited metabolic defect of Wilson's disease, where the liver's capacity to synthesize ceruloplasmin is compromised. This results in a reduced excretion of copper and its chronic accumulation of in tissues.
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