Carp muscle calcium-binding protein. I. Characterization of the tryptic peptides and the complete amino acid sequence of component B.

The amino acid sequence of carp muscle calcium-binding protein B has been completely determined by a combination of chemical and x-ray data. The protein was subjected to tryptic digestion and the peptides were separated on ion exchange columns. All of the 108 residues of the protein could be accounted for in 15 tryptic peptides. The sequence of each peptide was elucidated by a combination of Edman degradations with dansylation, carboxypeptidase, and aminopeptidase hydrolyses, and high voltage electrophoresis at pH 6.5. One 19-residue tryptic peptide was resistant to Edman degradation and was found by mass spectral analysis to have N-acetylalanine at the NH2 terminus. The sequence of this peptide was determined after digestion with thermolysin. The alignment of both the thermolytic and tryptic peptides to give the over-all sequence was made primarily from the 2.0 A resolution electron density map.