[Determination of apparent mean mass of proteins associated with heme in the hemoglobin molecule of Arenicola marina (L.), Annelida, Polychaeta].

Protein and iron concentrations and maximum combined oxygen concentration were measured in the blood of the lugworm Arenicola marina. The calculated mean molecular mass of the heme-associated proteins was higher than that reported for known invertebrate and vertebrate intracellular hemoglobins. The difference is probably due to the presence of polypeptide chains not linked to heme groups in the extracellular annelid hemoglobins.