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Any of the iron-porphyrin protein respiratory pigments found in the blood and tissue fluids of certain invertebrates; corresponds to hemoglobin in vertebrates.



a hemoglobin (oxygen-carrying pigment) of certain invertebrates, such as leeches and Daphnia. Unlike the hemoglobins in vertebrates, erythrocruorin is found not in the erythrocytes but in the hemolymph or blood plasma (usually in dissolved form). Erythrocruorin has a higher molecular weight than hemoglobin in vertebrates (2,750,000–3,000,000), since the pigments dissolved in the blood usually form large molecular aggregates.

References in periodicals archive ?
Cationic control of [O.sub.2] affinity in lugworm erythrocruorin. Nature 292: 386-387.