Plants galactose oxidase

Copper is one of the twenty-seven elements known to be essential to humans (69—72) (see Mineral nutrients). The daily recommended requirement for humans is 2.5—5.0 mg (73). Copper is probably second only to iron as an oxidation catalyst and oxygen carrier in humans (74). It is present in many proteins, such as hemocyanin [9013-32-3] galactose oxidase [9028-79-9] ceruloplasmin [9031 -37-2] dopamine -hydroxylase, monoamine oxidase [9001-66-5] superoxide dismutase [9054-89-17, and phenolase (75,76). Copper aids in photosynthesis and other oxidative processes in plants. 

The oxidation state of copper in biological systems is -1-1 or +2. Copper(III) is found in inorganic systems and may occur as a reaction intermediate in galactose oxidase, laccase (a plant enzyme), and perhaps other enzymes. The coordination number of copper in these enzymes ranges from two to six and occasionally higher. 

Copper is an essential trace element for humans and other animals. Copper ions are included in the active centres of many enzymes, especially cytochrome c oxidase, superoxide dismutase, various aminoxidases (such as lysyl oxidase), hydroxylases (e.g. dopamine -hydroxylase and tyrosinase), galactose oxidase or different phenoloxidases, such as laccase and other oxidoreductases. The so-called blue copper proteins, for example plastocyanin, azurin and plantacyanin, occur in many prokaryotic organisms and plants. These proteins, by a change to the bound copper valency, provide electron transfer in various redox processes. 

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