Studies on hemoglobin from the hagfish Epatatretus burgeri.

Ultracentrifugation studies on hemolysates from the erythrocytes of the hagfish, Eptatretus burgeri, showed that in dilute solution oxygenated hemoglobins were in a monomeric form with a molecular weight of approximately 18,000. In deoxygenated hemolysates or in concentrated solutions of oxygenated hemolysates, an aggregate product appeared which was considered to be a tetramer, as judged from its sedimentation coefficient. Contrary to a previous report, the hemolysate of the hagfish showed weak but significant heme-heme interaction (n = 1.2) depending on its hemoglobin concentration and pH. In the hemolysate, four hemoglobin components were found by electrophoresis, and other hemoglobins, if any, were very small in amount. The four components were preparatively separated by chromatography on DEAE-cellulose and hydroxylapatite. Among them only one component, F3, aggregated slightly by itself, whereas the other three hemoglobins did not. No components in their isolated state showed significant heme-heme interaction. The hemoglobins of E. burgeri could be divided into two classes; one (Fl and probably F2) hardly aggregated with any other components, and the components of the other (F3 and F4) aggregated with each other, especially in the deoxygenated state, and formed a hybrid tetramer which showed heme-heme interaction.