Effects of Sugar Chain Precursors on Recombinant Protein Production in BHK Cells

摘要

Glycosylation of bioactive proteins is a pivotal posttranslational modification for their biological activities, and therefore constant production of glycoproteins with high levels of glycosylation is required for industrial production. Among the residues in sugar chains, sialic acids are important for the in vivo stability of glycoproteins and high levels of sialylation are desirable. However, sialic acids are scarcely able to be incorporated from the medium. N-acetyl-D-mannosamine (ManNAc), an intracellular precursor for sialic acid synthesis, has been tested as a culture substrate for improving sialylation. In the present study, the influences of ManNAc on cell proliferation and product yield were investigated. ManNAc was added to cultures of BHK-EPO cells producing a recombinant EPO protein as a model for glycoprotein production. Although the cell proliferation was seriously inhibited in the presence of 200 mM ManNAc, the recombinant protein production was improved. Analysis by two-dimensionalelectrophoresis revealed that the EPO glycosylation level was improved in the presence of ManNAc. These results imply that BHK cells would be suitable for producing glycoproteins with high levels of sialylation in the presence of concentrated ManNAc.