Copper. Element. Essential trace nutrient.
Evolutionarily, Cu is the metal atom at the centre of haemocyanin, a pigment which performs the same function for most molluscs and various arthropods and crustaceae as haemoglobin does for us. Copper is frequently present in oxidases. It functions in the crosslinking and strengthening of collagen. Caeruloplasmin and transcuprein specifically bind Cu.
Copper has a slight disinfectant effect. Influenza viruses were noted to stay viable for shorter on copper door-handles than steel, and it is now understood that copper wire wound on IUCDs may help reduce susceptibility to pelvic inflammatory disease as well as increasing their contraceptive efficacy considerably.
There are important relationships with zinc metabolism and the two ions tend to have complimentary biological roles. Superoxide dismutase has copper at its active site, but does include zinc