Chemical and Enzymatic Synthesis of Sialylated Glycoforms of Human Erythropoietin

Recombinant human erythropoietin (EPO) is the main therapeutic glycoprotein for treatment of anemia in cancer and kidney patients. The in-vivo activity EPO carbohydrate-dependent with number sialic acid residues regulating its circulatory half-life. carries three N-glycans thus obtaining pure glycoforms provides a major challenge. We have developed robust reproducible chemoenzymatic approach to without acids. was assembled by sequential native chemical ligation two peptide glycopeptide segments. glycopeptides were obtained pseudoproline-assisted Lansbury aspartylation. Enzymatic introduction acids readily accomplished at level segments but even more efficiently on refolded glycoprotein. Biological recognition synthetic EPOs shown formation 1:1 complexes recombinant receptor.