Hemocyanins are copper-containing oxygen carriers occurring freely dissolved in the hemolymph of many mollusks and arthropods. Scorpion hemocyanin is a 24-chain polymer with 8 different chains identified, assembled in hexameric substructures. Hemolymph. Three disulfide bonds are present. The two copper ions bound each have 3 nitrogen ligands (presumably contributed by His residues) and share a bridging ligand (possibly contributed by a Tyr residue) in addition to binding oxygen. Belongs to the tyrosinase family. Hemocyanin subfamily.