Synthesis and biological activity of some glucose‐enkephalin conjugates

Abstract

Two O-glucopeptides, H-Tyr(beta-D-Glc)-Gly-Gly-Phe-OH(10) and H-Tyr(beta-D-Glc)-Gly-Gly-Phe-Leu-OH (11), having the amino acid sequence of enkephalin, were synthesized to determine the influence of the carbohydrate molecule on the biological activity and conformation of these opioid peptides. The synthesis were carried out in a stepwise and/or direct manner by fusing the activated O-glucosylpseudourea intermediate with suitably protected amino acid or peptide derivatives, followed by hydrogenolytic removal of protecting groups. The pure compounds were tested for opiate-like activity by using the guinea pig ileum (GPI) and mouse vas deferens (MVD) preparations.