Studies on the Hemoglobins of Pinnipeds

The hemoglobins of seven species of pinnipeds—elephant, ribbon, fur, harbor, and grey seals, walrus, and California sea lion—had two major and one minor hemoglobin fractions on electrophoresis at pH 8.6. One of the major fractions in all seven species had the same electrophoretic mobility. The second fractions of the gray, harbor, and ribbon seals were similar, but different from the second fractions of the walrus, fur seal, and sea lion. The second fraction of the elephant seal was different from all the others. The proportion of the two major fractions was about 3:1 in the elephant, grey, ribbon, and harbor seals, and about 1:1 in the fur seal, walrus, and sea lion. These results correlated well with the pinniped phylogenetic chart derived by classical morphology. All hemoglobin fractions were found to be alkali sensitive and heat stable. Gel filtration studies with Sephadex G-75 and G-100 indicated that the elephant seal hemoglobins had a mol wt of about 65,000. The amino acid compositions of the chains isolated from the hemoglobin fractions suggested that in the elephant seal one major fraction had two alpha and two beta chains, and the other major fraction had four like chains. The presence of a hemoglobin which is composed of a tetramer of like chains could be functionally advantageous to deep diving mammals.