MICROPURIFICATION AND AMINO-ACID-SEQUENCE OF BETA-CASOMORPHIN-8 IN MILK FROM A WOMAN WITH POSTPARTUM PSYCHOSIS

Milk was obtained from a woman with acute postpartum psychosis and wit h ongoing lactation. Defatted samples were subjected to micropurificat ion and collected fractions were analyzed by means of their beta-casom orphin-8 immunoreactivity. Immunoreactive material with the same chrom atographic properties as synthetic human beta-casomorphin-8 was determ ined by amino acid sequence analysis to be Tyr-Pro-Phe-Val-Glu-Pro-Ile -Pro. Its molecular mass was determined by fast atom bombardment-mass spectrometry to be 962.3 Da. These determinations, which ultimately id entify the immunoreactive material as human beta-casomorphin-8, repres ent the first structural identification of a beta-casomorphin peptide from a body fluid.