pubmed:abstractText |
The thiolcarboxyl peptide [17-thiolglycine]-beta-endorphin-(1-17) (I) was synthesized by the solid-phase method. Reaction of peptide I with citraconic anhydride gave citraconyl-[Lys(Cit9,GlyS17]-beta-endorphin-(1-17) (Ia). Peptide Ia was coupled to another synthetic peptide, [Lys(Cit)19,24,28,29]-beta-endorphin-(18-31), by reaction with silver nitrate--N-hydroxysuccinimide in water. All citraconyl groups were removed in aqueous acetic acid, and [Gly17]-beta-endorphin was isolated in 30-40% yield. The synthetic analog had 10% analgesic potency and 59% opiate--receptor binding activity when compared with human beta-endorphin.
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