beta-endorphin: synthesis of analogs with extension at the carboxyl terminus with high radioreceptor binding activity.

International journal of peptide and protein research

PubMedID: 6254896

Yamashiro D, Ferrara P, Li CH. beta-endorphin: synthesis of analogs with extension at the carboxyl terminus with high radioreceptor binding activity. Int J Pept Protein Res. 1980;16(1):70-4.
Four analogs of human beta-endorphin (beta h-EP) have been synthesized: [Gly31]-Beta h-EP-Gly-NH2, [CH3(CH2)4NH231]-beta h-EP, [Gly31]-beta h-EP-Gly-Gly-NH2, and [Gln8, Gly31]-betah-EP-Gly-Gly-NH2. All are more active than beta h-EP in an opiate receptor binding assay. Stepwise extension at the COOH-terminus shows a progressive increase in binding activity. The last analog, which combines extension at the COOH-terminus with elimination of the remaining anionic charge in beta h-EP, is nine times more active than the parent molecule.