Premium
Ammonia affects the glycosylation patterns of recombinant mouse placental lactogen‐I by chinese hamster ovary cells in a pH‐dependent manner
Author(s) -
Borys Michael C.,
Linzer Daniel I. H.,
Papoutsakis Eleftherios T.
Publication year - 1994
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260430611
Subject(s) - chinese hamster ovary cell , ammonium chloride , glycosylation , extracellular , recombinant dna , ammonium , chemistry , biochemistry , ammonia , placental lactogen , secretion , biology , placenta , receptor , pregnancy , fetus , genetics , organic chemistry , gene
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 m M ) in a serum‐free, protein expression medium. The effect of ammonia on glycosylation was dependent on the extracellular pH (pH e ). In media containing 0 and 9 m M ammonium chloride, the percentage of the most heavily glycosylated forms of secreted mPL‐I decreased from ca. 90% to ca. 25% at pH e 8.0, and from ca. 90% to ca. 65% at pH e 7.6, respectively. However, at pH e 7.2, the most heavily glycosylated forms of secreted mPL‐I decreased from ca. 90% to ca. 80% in media containing 0 and 9 m M ammonium chloride, respectively. Inhibition of mPL‐I glycosylation was found to correlate with the calculated concentrations of the ammonia species (NH 3 ). 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 m M , inhibited the expression rate of MPL‐I by CHO cells at low pH e . © 1994 John Wiley & Sons, Inc.