Hemocyanins are copper-containing oxygen carriers occurring freely dissolved in the hemolymph of many mollusks and arthropods. Hexamer of a number of different chains, of which five have been identified. Hemolymph. Contains one N-glycosylated and three O-glycosylated residues. The position of one of the O-glycosylated residues has not been determined. O-linked glycan at Ser-120 may be composed of two GalNAc, three Gal, and two N-acetylneuraminic acid units for a total 1525-Da MW. Belongs to the tyrosinase family. Hemocyanin subfamily.