Metabolism of recombinant CHO-GS cell reducing of toxic effect of ammonia.
- Author:
Fang ZHANG
1
;
Xiao-Ping YI
;
Xiang-Ming SUN
;
Yuan-Xing ZHANG
Author Information
1. State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
- Publication Type:Journal Article
- MeSH:
Ammonia;
metabolism;
toxicity;
Animals;
CHO Cells;
Cell Culture Techniques;
methods;
Cricetinae;
Cricetulus;
Culture Media, Serum-Free;
Genetic Engineering;
methods;
Glutamate-Ammonia Ligase;
genetics;
metabolism;
Glutamine;
metabolism
- From:
Chinese Journal of Biotechnology
2006;22(1):94-100
- CountryChina
- Language:Chinese
-
Abstract:
The toxic effect of ammonia on rCHO-GS cell decreased obviously due to the transfection of GS system in serum-free culture. The maximum cell density, 15.6 x 10(5) cells/mL was obtained in the culture with 1.42 mmol/L ammonia. The growth of rCHO-GS cell was inhibited with an increased ammonia concentration. However, a cell density of 8.9 x 10(5) cells/mL was obtained when the concentration of ammonia was 12.65mmol/L. The intracellar metabolic pathways were affected due to the decrease of the toxic effect of ammonia on rCHO-GS cell. With the increase of initial ammonia concentration from 0.36mmol/L to 12.65mmol/L, the yield coefficients of cell to glucose and lactate to glucose decreased. The activities of hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) increased by 43%, 140% and 25%, respectively, indicating that the utilization of glucose increased and the glycolysis pathway was more prone to efficient energy metabolism pathway. An increased activity of glutamate-pyruvate aminotransferase (GPT) showed that the conversation from glutamate to alpha-ketoglutarate was shifted to glutamate-pyruvate transamination pathway. The deamination pathway was inhibited due to a decreased activity of glutamate dehydrogenase. In addition, the number of cells in G0/G1 phase increased and the specific production rate of recombinant protein increased by 2.1-fold with the increase of initial ammonia concentration from 0.36mmol/L to 12.65mmol/L.
