1-(N-(1-L-Tyrosyl-L-prolyl)-L-phenylalanyl)-L-proline 74171-19-0 L-Proline, 1-(N-(1-L-tyrosyl-L-prolyl)-L-phenylalanyl)- Tyr-pro-phe-pro Tyrosyl-prolyl-phenylalanyl-proline beta-Casomorphin 4 beta-Casomorphin 4 (ox)