hemocyanin

The protein, called hemocyanin, is pale yellow when not combined with oxygen, and blue when combined with oxygen. The molecular weights of hemocyanins vary from 300,000 to 9,000,000. Each animal investigated thus far apparently has a species-specific hemocyanin.

Copper-containing proteins called hemocyanins occur notably in the blood of larger crustaceans and of gastropod and cephalopod mollusks. Hemocyanins are colourless in the reduced, or deoxygenated, state and blue when exposed to air or to oxygen dissolved in the blood. Hemocyanins serve as respiratory…

Hemocyanin, a copper-containing protein chemically unlike hemoglobin, is found in some crustaceans. Hemocyanin is blue in colour when oxygenated and colourless when oxygen is removed. Some annelids have the iron-containing green pigment chlorocruorin, others the iron-containing red pigment hemerythrin. In many invertebrates the respiratory pigments…

Hemocyanins are copper-containing respiratory pigments found in many mollusks (some bivalves, many gastropods, and cephalopods) and arthropods (many crustaceans, some arachnids, and the horseshoe crab, Limulus). They are colourless when deoxygenated but turn blue on oxygenation. The copper is bound directly to the protein, and…

…most mollusks, including cephalopods, contains hemocyanin, although a few gastropods use hemoglobin. In the cephalopods the pigment unloads at relatively high oxygen pressures, indicating that it is used to transport rather than store oxygen.