Definition of hemocyanin in US English:


(British haemocyanin)


  • A protein containing copper, responsible for transporting oxygen in the blood plasma of arthropods and mollusks.

    • ‘Injection of bacteria had no influence on hemocyanin or hemolymph protein concentrations when compared to saline injection.’
    • ‘It is intriguing that crustaceans seem to express either hemoglobin or hemocyanin but not both proteins.’
    • ‘The ontogeny of crustacean hemocyanin, the copper-based oxygen transport protein, has been studied in relatively few species, including Nephrops norvegicus and Homarus americanus.’
    • ‘The focus of this paper is on the Crustacea, the class of Arthropoda that expresses both hemoglobin and hemocyanin.’
    • ‘One grasshopper embryo has a protein that closely resembles hemocyanin in sequence, but no oxygen binding studies to confirm its function have yet been done.’


Mid 19th century: from hemo- ‘of blood’ + cyan + -in.