SYNTHESIS OF THE GLYCOSYL AMINO-ACIDS C-4-BETA-D-GALP-(1-]3)-AC-2-ALPHA-D-GALN(3)P]-OPFP AND C-4-BETA-D-GALP-(1-]3)-AC-2-ALPHA-D-GALN(3)P]-OPFP AND THE APPLICATION IN THE SOLID-PHASE PEPTIDE-SYNTHESIS OF MULTIPLY GLYCOSYLATED MUCIN PEPTIDES WITH T-N AND T-ANTIGENIC STRUCTURES

Two new glycosyl amino acids N-alpha-Fmoc-Ser[Ac-4-beta-D-Gal p-(1 --> 3)-Ac-2-alpha-D-GalN(3) p]-OPfp and N-alpha-Fmoc-Thr[Ac-4-beta-D-Gal p-(1 --> 3)-Ac-2-alpha-D-GalN(3) p]-OPfp were synthesized. Glycosylati on of N-alpha-Fmoc-Ser-OPfp or N alpha-Fmoc-Thr-OPfp with protected be ta-D-Gal-(1 --> 3)-D-GalN(3) donors afforded the glycosyl amino acids containing an activated C-terminus which could be utilized directly fo r solid-phase glycopeptide synthesis. The transformation of the 2-azid o group into the acetamido derivative was achieved quantitatively at t he end of the synthesis by treatment of the polymer-bound glycopeptide with thioacetic acid. The versatility of this strategy was demonstrat ed by the assembly of eight triply glycosylated mucin peptides which w ere synthesized simultaneously by multiple column techniques. The glyc opeptides were prepared in order to investigate the substrate specific ity of a galactosyltransferase.