The Intracellular Hemoglobins of a Polychaete

Abstract

Abstract The erythrocytes of the polychaete annelid Glycera dibranchiata contain two hemoglobins that are separable by gel filtration or electrophoresis. Gel filtration and ultracentrifugation studies of the smaller of the two hemoglobins show that it possesses a molecular weight of 17,000 to 18,000 at neutral pH; its iron content is 0.318 ± 0.015 weight per cent. The other hemoglobin has a molecular weight of about 39,000 at pH 7.4 to 8.5, and an iron content of 0.293 ± 0.010 weight per cent. Disc electrophoresis of the two hemoglobins at pH = 7.4 in the presence of sodium dodecyl sulfate produces a single band corresponding to a molecular weight of 17,000 + 1,000. The amino acid compositions of the two hemoglobins are found to be different. In the presence of urea concentrations greater than 4 m, i.e. under conditions where the s20,w values for both hemoglobins are equal, disc electrophoresis at pH 8.25 reveals that both are polymorphic.