VV-HEMORPHIN-7 AND LVV-HEMORPHIN-7 RELEASED DURING IN-VITRO PEPTIC HEMOGLOBIN HYDROLYSIS ARE MORPHINOMIMETIC PEPTIDES

Two opioid peptides were generated by in vitro pepsin treatment of bov ine hemoglobin. These peptides were identified using a GPI test and pu rified using HPLC chromatographic techniques. They correspond to fragm ents 31-40 (LVV-hemorphin-7) and 32-40 (VV-hemorphin-7) of the beta-ch ain of bovine hemoglobin. Binding experiments strongly confirm that VV -hemorphin-7 and LVV-hemorphin-7 are opioid peptides since they inhibi ted [H-3]naloxone binding to rat brain membranes. Our results indicate that VV-hemorphin-7 and LVV-hemorphin-7 exhibit a lesser potency both in GPI and binding tests. Selectivity and affinity of these purified peptides and synthetic hemorphin-7 for opioid receptors is discussed.