Isolation, characterization and opiate activity of beta-endorphin from the pituitary gland of the ostrich, Struthio camelus.

1. Avian beta-endorphin was purified from adenohypophyseal glands of the ostrich Struthio camelus by a procedure involving acid/acetone extraction, NaCl fractionation, CM-cellulose chromatography, Sephadex G-50 chromatography and paper electrophoresis (pH 6.7). 2. The 31-amino acid peptide behaved as a single substance during polyacrylamide-gel electrophoresis and isoelectric focusing, the isoelectric point being 8.84. 3. Ostrich beta-endorphin exhibited significant opiate activity in the guinea-pig ileum preparation.