Copper in the organism--transport and storage in the cells.

Copper functions as cofactor in various redox enzymes. At the same time, copper is very toxic to both eukaryotic and prokaryotic cells. Copper ions can bind to proteins and nucleic acids and cause the oxidation of lipids and proteins. The formation of deleterious free radicals is also enhanced by copper ions. For cell viability, regulation of intracellular copper activity is thus crucially important and mechanisms must exist for the homeostasis of copper.