Isolation and properties of a tryptophan-containing peptide from bovine and turkey brains

A tryptophan-containing peptide has been isolated from bovine cerebral hemispheres. A similar peptide has also been isolated from the turkey brain. Isoelectric focusing on polyacrylamide gels shows the peptides to be essentially homogeneous. Both peptides consist of 67 amino acids with isoleucine at the COOH-terminus. The NH2-terminal residues cannot be detected by end-group analysis. Both peptides exhibit 45--50% alpha-helix as revealed by circular dichroism spectra.