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J.Biol.Chem. 244 (8): 2149-2158 (1969)
Comparison of myoglobins from harbor seal, porpoise, and sperm whale III. Isolation and characterization of the tryptic peptides of harbor seal myoglobin
RA Bradshaw , WH Garner , FRN Gurd
Harbor seal myoglobin has been dehemed and treated with bromoacetate in 8 M urea for 9 days at pH 6.7 to produce
a derivative that was exhaustively alkylated at the
histidyl residues. In addition, both the methionyl residues
and the amino-terminal glycyl residue were modified.
The alkylated derivative was subjected to tryptic digestion
and the hydrolysate was fractionated on columns of
Dowex 50 and Dowex 1 with gradients of pyridine acetate.
All of the peptides recovered could be aligned by analogy
to the known sequence of the closely related sperm whale
myoglobin to give a tentative sequence. By this technique,
85 of the 153 residues could be positioned from sequential
Edman degradations or carboxypeptidase hydrolyses.
Of the established group, 15 residues were different from
those in the corresponding sperm whale protein and, from
compositional data, a minimum of 10 additional replacements
must also exist. Thus, excluding amide differences, the
seal protein differs from the sperm whale protein in at least
25 positions. The tentative partial sequence obtained was
in exact agreement with the previously established amino
acid composition of the protein.
1969///Comparison of myoglobins from harbor seal, porpoise, and sperm whale III. Isolation and characterization of the tryptic peptides of harbor seal myoglobinJOUR