from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A bluish, copper-containing protein with an oxygen-carrying function similar to that of hemoglobin, present in the blood of certain mollusks and arthropods.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. a blue copper-containing respiratory pigment (a metalloprotein) found in most molluscs, and some arthropods

from The Century Dictionary and Cyclopedia

  • n. The coloring matter of the blood of various invertebrates. It contains copper. It is blue when oxidized, and colorless in the deoxidized state.


Sorry, no etymologies found.


  • In us, the oxygen is carried to the tissues, and the carbon dioxide carried away by an iron compound, hemoglobin, but in many animals of Earth, the same function is performed by a copper compound, hemocyanin, which is an intense blue.

    The Black Star Passes

  • Squids also use hemocyanin instead of hemoglobin - thus the protein that carries oxygen in their blood is copper-based, like Spock's on Star Trek.


  • The main toxic action of NO3 – on aquatic animals, particularly on fish and crayfish, seems to be the conversion of oxygen-carrying pigments (hemoglobin, hemocyanin) to forms that are incapable of carrying oxygen (methemoglobin, methemocyanin).

    Inorganic nitrogen pollution in aquatic ecosystems~ causes and consequences

  • Similarly, in crayfish, entry of nitrite into the blood plasma is associated with the oxidation of copper atoms (Cu1+ → Cu2+), whereby functional hemocyanin is converted into methemocyanin that cannot bind reversibly to molecular oxygen.

    Inorganic nitrogen pollution in aquatic ecosystems~ causes and consequences

  • This line of thinking led me to suggest to Thorsten Burmester, an expert on arthropod gas exchange proteins, that he should check to see if stoneflies have hemocyanin in their blood.

    Pharyngula: An evolutionary prediction - The Panda's Thumb

  • Burmester found that stoneflies do indeed have hemocyanin in their blood Proceedings of the National Academy of Sciences 101: 871-874 that reversibly binds oxygen, and it appears that no other pterygote insects possess this trait.

    Pharyngula: An evolutionary prediction - The Panda's Thumb

  • Why mammals have a common blood structure (Types A,B,O also in chimps) based on cells, in contrast to circulating proteins (cf. hemocyanin, a copper-based porphyrin oxygen-carrier found in e.g. lobsters).

    The Great Debate - The Panda's Thumb

  • Hemoglobin, such as in our blood, and hemocyanin, like that in the blue blood of the Venerians, are practically unique in that respect.

    The Black Star Passes

  • The DC were also exposed to keyhole limpet hemocyanin (KLH), which was used as a surrogate marker to show an immune response.

    Newswise: Latest News

  • In cerithioid hemocyanin tridecamers ( "mega-hemocyanin") the collar complex of the central decamer is substantially enlarged and modified.

    BioMed Central - Latest articles


Log in or sign up to get involved in the conversation. It's quick and easy.