• binding assays;
  • glycosylated rigins;
  • peptide synthesis in solution;
  • phagocytosis;
  • pseudoglycopeptides;
  • rigin

Synthesis of some modified rigins is described in which either D-gluconic acid or 2-amino-2-deoxy-β-D-glucopyranose have been linked to the parent molecule through amide bonds involving the α-amino function, α-carboxyl function or the γ-amide function of glutamine in position 2. Glu2-rigin and D-gluconyl-Glu2-rigin have also been synthesized. Binding and phagocytosis assays have been carried out on the rigin derivatives and on some glycosylated tuftsin derivatives as well. Of all the tested peptides only rigin enhanced the phagocytic capacity of mouse peritoneal macrophages to the same extent as tuftsin. The peptides H-Thr-Lys-Pro-Arg-NH-Glc and Nα-gluconyl-Gly-Glu-Pro-Arg-OH slightly enhanced phagocytosis. H-Thr[(α + β)-O-glucosyl]-Lys-Pro-Arg-OH was found to displace 3H-tuftsin even better than tuftsin but lacked the ability to stimulate phagocytosis.