Recognition of Primary Sequence Variations among Sperm Whale Myoglobin Components with Successive Proteolysis Procedures

Analyses of peptide fragments from Fraction IIIB confirm the distinction from the main component (Fraction IV) based on over-all analysis and establish the genetic multiplicity of the myoglobin in an individual sperm whale specimen.

Abstract

SUMMARY The minor components of sperm whale myoglobin, Fractions IIIB, IIIA, and II, have been separated from the main component, Fraction IV, most conveniently on SP- or SESephadex. The fractions were analyzed for amino acid composition by standard methods and also by enzymatic digestion with a protease followed by carboxypeptidase C and aminopeptidase M. The three minor fractions differ in composition from each other and from the main fraction. The differences from the main fraction are least for Fraction IIIB and greatest for Fraction IIIA, following the terminology of Nakhleh ((1972) Ph.D. thesis, American University of Beirut). Analyses of peptide fragments from Fraction IIIB confirm the distinction from the main component (Fraction IV) based on over-all analysis. In addition to the long suspected differences in amide content these results reveal other compositional differences and establish the genetic multiplicity of the myoglobin in an individual sperm whale specimen. The observed variations are comparable in degree to those seen among the main components represented in distinct animal species.