Complete primary structure of the major component myoglobin of California gray whale (Eschrichtius gibbosus)

Abstract

The complete primary structure of the major component myoglobin [Mb] from the California gray whale, E. gibbosus, was determined by specific cleavage of the protein to obtain large peptides for degradation by the automatic sequenator. Cleavage at the 2 methionine residues of the apoMb with cyanogen bromide and at the 3 arginine residues of the methyl acetimidated protein with trypsin resulted in 3 and 4 easily separable peptides, respectively, which when sequenced accounted for 85% of the primary structure. The remainder of the covalent structure was obtained by further digestion of the central cyanogen bromide peptide with trypsin and Staphylococcus aureus strain V8 protease. This protein differs from that of the sperm whale, Physeter catodon, at 12 positions, from that of the common porpoise, Phocoena phocoena, and the Black Sea dolphin, Delphinus delphis, at 14 positions, and from that of the Amazon River dolphin, Inia geoffrensis, at 7 positions. All substitutions observed in this sequence fit easily into the tertiary structure of sperm whale Mb.