Isolation and properties of beta-endorphin-(1-27)-like peptide from bovine brains

A beta-endorphin-(1-27)-like peptide was isolated from bovine cerebral hemisphere extracts by gel filtration, ion-exchange chromatography, high performance liquid chromatography and paper electrophoresis. The peptide had tyrosine as the amino-terminal residue and its amino acid composition was nearly identical to that of equine pituitary beta-EP-(1-27). It had also the same mobility as equine pituitary beta-EP-(1-27) in paper electrophoresis. In radioimmunoassay and opiate receptor-binding assay, the brain peptide had 50% activity when compared with human beta-endorphin-(1-27). Evidence for the occurrence of NH2-acetylated form of beta-endorphin-(1-27) is also presented.