Ammonia affects the glycosylation patterns of recombinant mouse placental lactogen‐I by chinese hamster ovary cells in a pH‐dependent manner

Michael C. Borys*, Daniel I.H. Linzer, Eleftherios T. Papoutsakis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

93 Scopus citations

Abstract

The N‐linked glycosylation of the recombinant protein mouse placental lactogen‐I (mPL‐I) expressed by Chinese hamster ovary (CHO) cells under nongrowth conditions was inhibited by increasing levels of ammonium chloride (3 and 9 mM) in a serum‐free, protein expression medium. The effect of ammonia on glycosylation was dependent on the extracellular pH (pHe). In media containing 0 and 9 mM ammonium chloride, the percentage of the most heavily glycosylated forms of secreted mPL‐I decreased from ca. 90% to ca. 25% at pHe 8.0, and from ca. 90% to ca. 65% at pHe 7.6, respectively. However, at pHe 7.2, the most heavily glycosylated forms of secreted mPL‐I decreased from ca. 90% to ca. 80% in media containing 0 and 9 mM ammonium chloride, respectively. Inhibition of mPL‐I glycosylation was found to correlate with the calculated concentrations of the ammonia species (NH3). Control experiments showed that the ammonia effect on mPL‐I glycosylation could not be attributed to increased chloride concentration or osmolarity, or to extracellular events after secretion of the recombinant protein into the supernatant. Ammonium chloride, 9 mM, inhibited the expression rate of MPL‐I by CHO cells at low pHe. © 1994 John Wiley & Sons, Inc.

Original languageEnglish (US)
Pages (from-to)505-514
Number of pages10
JournalBiotechnology and Bioengineering
Volume43
Issue number6
DOIs
StatePublished - Mar 15 1994

Keywords

  • CHO cells
  • ammonia
  • glycosylation
  • pH
  • placental lactogen
  • recombinant protein expression

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

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