2 research outputs found
Chemical and Enzymatic Synthesis of Sialylated Glycoforms of Human Erythropoietin
Recombinant human erythropoietin (EPO) is the main therapeutic glycoprotein for the treatment of anemia in cancer and kidney patients. The inâvivo activity of EPO is carbohydrateâdependent with the number of sialic acid residues regulating its circulatory halfâlife. EPO carries three Nâglycans and thus obtaining pure glycoforms provides a major challenge. We have developed a robust and reproducible chemoenzymatic approach to glycoforms of EPO with and without sialic acids. EPO was assembled by sequential native chemical ligation of two peptide and three glycopeptide segments. The glycopeptides were obtained by pseudoprolineâassisted Lansbury aspartylation. Enzymatic introduction of the sialic acids was readily accomplished at the level of the glycopeptide segments but even more efficiently on the refolded glycoprotein. Biological recognition of the synthetic EPOs was shown by formation of 1:1 complexes with recombinant EPO receptor