Hemocyanins are copper-containing oxygen carriers occurring freely dissolved in the hemolymph of many mollusks and arthropods. It consists of at least four very similar subunits. Hemolymph. Belongs to the tyrosinase family. Hemocyanin subfamily. The sequence has been determined from a mixture of all the subunits and so the exact sequence as well as the relevance of the variants described is unknown for each subunit.