title: Beta-endorphin: replacement of tyrosine in position 27 by tryptophan increases analgesic potency--preparation and properties of the 2-nitrophenylsulfenyl derivative.
abstract: An analog of human beta-endorphin with tryptophan in position 27 has been synthetized by the solid-phase method. Bioassay of the analog showed that it had almost 4 times the analgesic potency of the parent hormone but only 68% of the opiate receptor-binding activity. The peptide is the most potent analgesic among the known synthetic analogs of beta-endorphin. The 2-nitrophenylsulfenyl derivative of the analog has been prepared and shown to have a lower analgesic potency and a higher opiate receptor-binding activity than the parent compound.
mesh_terms: D000595:Amino Acid Sequence; D000700:Analgesics; D000818:Animals; D004723:Endorphins / Q000138:chemical synthesis / Q000494:pharmacology*; D051381:Rats; D011957:Receptors, Opioid / Q000378:metabolism; D013329:Structure-Activity Relationship; D001615:beta-Endorphin / Q000031:analogs & derivatives*
chemical_list: D000700:Analgesics; D004723:Endorphins; D011957:Receptors, Opioid; D001615:beta-Endorphin; C033847:beta-endorphin, Trp(27); C033848:beta-endorphin, Trp(27)-2-nitrophenylsulfenyl chloride