Primary structure of turkey myoglobin

Our objective was to determine the amino acid sequence of turkey myoglobin. Turkey myoglobin was isolated from cardiac muscles via ammonium sulphate precipitation and gel-filtration chromatography. Purified turkey myoglobin, separated as a 17 kDa band in SDS-PAGE, was subjected to digestion with trypsin or aspartic acid endopeptidase. The resulting peptides were separated by reverse-phase HPLC, and then subjected to Edman degradation to obtain the amino acid sequence. The complete amino acid sequence of turkey myoglobin was determined and compared with that of poultry and red meat myoglobins. Turkey myoglobin has 153 amino acids and nine histidine residues. Proximal (position 93) and distal (position 64) histidine residues, responsible for maintaining the stability of haeme, are conserved in turkey myoglobin. Turkey myoglobin shares 100% sequence similarity with chicken myoglobin, whereas it shares 92.5% homology with ostrich, 76.5% with pig, and less than 73% with ruminant myoglobins.