Comparison of primary structures of recombinant human erythropoietin marketed in China / 中国药学杂志

ABSTRACT

OBJECTIVE: To characterize and compare the primary structures of recombinant human erythropoietin marketed in China. METHODS: Recombinant human erythropoietin reference substances were obtained from nine manufacturers, for which the molecular mass, peptide mass mapping, oligosaccharide profile and content of sialic acid were analyzed and compared. RESULTS: The measured molecular masses of de-N-glycosylated EPO were all in agreement with the theoretical values with mass error less than 1. All the samples had consistent amino acid sequence, disulfide bonds (Cys7-Cys161, Cys29-Cys33), O-glycosylation site (Ser126), and N-glycosylation sites (Asn24, Asn38, Asn83), but different glycosylation pattern and ratio of glycoforms. The sialic acid content of the nine samples were within 11.5-15.7 mol∶mol EPO. CONCLUSION: Recombinant human erythropoietins from nine manufacturers have identical primary structures except for glycosylation patterns.