Myoglobins of Cartilaginous Fishes. II. Isolation and Amino Acid Sequence of Myoglobin of the Shark Mustelus Antarcticus

Abstract

Myoglobin isolated from red muscle of the gummy shark M. antarcticus was purified by gel filtration and ion-exchange chromatography on carboxymethyl cellulose in 8 M urea-thiol buffer. Amino acid analysis and sequence determination showed 148 amino acid residues. The amino terminal residue is acetylated as shown by nuclear magnetic resonance and mass spectrographic analysis of an N-terminal peptide. There is a deletion of four residues at the amino terminal end as well as one residue in the CD interhelical area relative to other myoglobins. These overall differences were also found previously in myoglobin of Heterodontus portusjacksoni.