, Volume 34, Issue 1–2, pp 83–99 | Cite as

Enhanced erythropoietin heterogeneity in a CHO culture is caused by proteolytic degradation and can be eliminated by a high glutamine level

  • M. Yang
  • M. ButlerEmail author


The molecular heterogeneity of recombinant humanerythropoietin (EPO) increased during the course of abatch culture of transfected Chinese hamster ovary(CHO) cells grown in serum-free medium. This wasshown by both an increased molecular weight and pIrange of the isolated EPO at the end of the culture. However, analysis of the N-glycan structures of themolecule by fluorophore-assisted carbohydrateelectrophoresis (FACE) and HPLC anion exchangechromatography indicated a consistent pattern ofglycosylation. Seven glycoforms were identified, thepredominant structure being a fully sialylatedtetra-antennary glycan. The degree of sialylationwas maintained throughout the culture. Analysis ofthe secreted EPO indicated a time-dependent increasein the molecular weight band width of the peptideconsistent with proteolytic degradation. A highglutamine concentration (16–20 mM) in the culturedecreased the apparent degradation of the EPO.

CHO cells erythropoietin glycosylation glutamine 


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Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  1. 1.Department of MicrobiologyUniversity of ManitobaWinnipeg, ManitobaCanada
  2. 2.Department of MicrobiologyUniversity of ManitobaWinnipeg, ManitobaCanada

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