Definition: One of the three major groups of endogenous opioid peptides. They are large peptides derived from the PRO-OPIOMELANOCORTIN precursor. The known members of this group are alpha-, beta-, and gamma-endorphin. The term endorphin is also sometimes used to refer to all opioid peptides, but the narrower sense is used here; OPIOID PEPTIDES is used for the broader group.
morphiceptin [ NH(4)-Tyr-Pro-Phe-Pro-CONH(2),Tyr-Pro-Phe-D-Pro-NH2,Tyr-Pro-Phe-Pro amide,beta-casomorphine(1-4) amide,deproceptin,morphiceptin monohydrochloride, (L-Tyr-L-Pro-L-Phe-L-Pro)-isomer,morphiceptin, (L-Tyr-D-Pro-L-Phe-L-Pro)-isomer,morphiceptin, (L-Tyr-L-Pro-L-Phe-D-Pro)-isomer,tyrosyl-prolyl-phenylalanyl-D-prolinamide ] synthetic tetrapeptide with morphinelike activities, highly specific for morphine receptors, but not for enkephalin receptors; is the amide of a fragment of the milk protein beta casein; deproceptin i