These are important copper-containing proteins involved in electron transfer.
This protein is a monomer, has a molecular weight of about 10,500 Da, and is 99 amino acids in most vascular plants.
It is a member of the copper-binding proteins plastocyanin family.
During photosynthesis, plastocyanins act as an electron transport chain between cytochrome f in the cytochrome b6f complex of Photosystem II and P700 + in Photosystem I.
With cytochrome b6f complex both P700 + are membrane-bound proteins with exposed residues on the luminal side of the chloroplast thylakoid membrane.
Cytochrome f acts as an electron donor and P700 + receives electrons from reduced plastocyanins.