An oxygen-carrying pigment (molecular weights between 0.45 and 13 × 106) of lower sea animals (including molluscs and crustacea) and arthropods; copper is an essential component, but it contains no heme; used as an experimental antigen.
* * *
he·mo·cy·a·nin or chiefly Brit hae·mo·cy·a·nin .hē-mō-'sī-ə-nən n a colorless copper-containing respiratory pigment in solution in the blood plasma of various arthropods and mollusks
* * *
he·mo·cy·a·nin (he″mo-siґə-nin) a nonheme blue respiratory pigment that is found in the blood plasma of many mollusks and arthropods and is composed of monomers each of which contains two atoms of Cu+ and can bind one molecule of O2.Medical dictionary. 2011.