Heterogeneity of the Hemoglobin from the Common Bloodworm Glycera dibranchiata

The hemoglobin from the annelid polychaete Glycera dibranchiata, present in large coelomic erythrocytes, was demonstrated to be of a heterogeneous nature with respect to both electrophoretic properties and molecular weight. On the basis of gel filtration, sedimentation velocity, and sedimentation equilibrium studies, 2 basic hemoglobin units were found: a monomer with a molecular weight of approximately 17,000 and a polydisperse higher order aggregate. The ratio of monomeric to polymeric hemoglobin was 0.85 (±0.10):1. Determination of iron content by atomic absorption spectroscopy and pyridine-hemochromogen determination revealed a minimum molecular weight of 18,400 to 19,700 for both monomer and polymer. Electrophoretic and ultracentrifugal studies of the globins obtained from the monomer and aggregate indicate the subunits are extremely similar with respect to molecular weight. Both the monomeric and polymeric globins gave similar patterms by disc gel electrophoresis. Each was found to contain two similar components. These data suggest that two hemoglobin monomers capable of polymerization are present.