The enkephalins and opiates: structure-activity relations.
The X-ray structures of 9 "opiate" drugs which exhibit a range of pharmacological activity have been examined in detail leading to the theory that one of the reasons why the enkephalins and related peptides possess morphine-like activity is because they have a tyrosine, and hence a "tyramine", residue at the amino terminal position. This residue or a conformationally similar moiety, can be shown to be present in many opiates and analogues.
D000595:Amino Acid Sequence; D000701:Analgesics, Opioid / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D004745:Enkephalins / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008968:Molecular Conformation; D009294:Narcotics / Q000378:metabolism / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D011957:Receptors, Opioid / Q000378:metabolism; D013329:Structure-Activity Relationship; D014961:X-Ray Diffraction
D000701:Analgesics, Opioid; D004745:Enkephalins; D009294:Narcotics; D009842:Oligopeptides; D010455:Peptides; D011957:Receptors, Opioid