Covalent Structure Of Beef Heart Myoglobin

The covalent structure of beef myoglobin is being investigated through different experimental approaches. The globin was cleaved by cyanogen bromide. The resulting fragments were fractionated and submitted to tryptic and chymotryptic digestions. The complete amino acid sequence of these peptides has been established. From the overlaps in sequence between chymotryptic and tryptic peptides, it is possible to place most of these peptides of 153 residues of beef myoglobin in unique sequence. The remaining residues have been ordered on the basis of the apparent homology in sequence between beef and horse myoglobins. The horse protein differs from that of beef in 18 positions. All of the amino acid replacements, except three, were confined to amino acid interchange caused by the change of one base in the coding triplet leaving 135 of 153 positions in the sequence invariant in the two proteins. The relations of these data to other is discussed.