Glutamine in Cell Culture
News 14 10 月, 2025
L-Glutamine, a coded amino acid in protein synthesis, is a common serum-free culture medium supplement used to support the proliferation and physiological functions of various mammalian cells. In commonly used culture media, glutamine concentrations range from 0.5 mM in Ames medium to 10 mM in MCDB 131 medium, typically between 2–4 mM.
Primary Functions
1. Energy Supply
Glutamine is an important metabolic energy source that meets the high cellular demand for ATP, biosynthetic precursors, and reducing agents in rapidly proliferating cells. It enters cells through amino acid transporters and is converted to glutamate in the mitochondria via a deamination reaction catalyzed by glutaminase (GLS).
Glutamate can then be converted into the TCA cycle intermediate α-ketoglutarate (α-KG) via glutamate dehydrogenase (GDH) or transaminases (TAs), generating ATP and replenishing TCA intermediates — a process known as anaplerosis.
2. Nitrogen Source
Glutamine is rich in amino groups and provides nitrogen for the synthesis of nucleic acids, proteins, and other biomolecules — essential for cell growth and division.
3. Buffering Effect
pH stability in culture medium is critical for cell growth and metabolism. Glutamine can act as a buffer, helping maintain a suitable acid-base balance for normal cell growth.
Potential Issues
1. Overuse
Although beneficial, excessive glutamine can disrupt amino acid metabolism, affect synthesis and utilization of other amino acids, and negatively impact cell growth and metabolism.
2. Stability Issues
Glutamine is sensitive to temperature, light, pH, and CO₂ concentration. Improper culture conditions may cause degradation, reducing its effectiveness.
Ready-to-use liquid media often contain free L-glutamine, which is chemically unstable, especially in bicarbonate/CO₂ buffering systems. Correct handling of L-glutamine–containing media is therefore essential.
Deamination is the main degradation reaction of L-glutamine in culture media, occurring under both acidic and alkaline conditions. The rate of deamination increases with higher pH, and is significantly accelerated in bicarbonate-buffered systems.
3. Contamination and Purity
Low-quality glutamine may contain impurities or harmful substances that negatively affect cell growth and health. Choosing high-quality glutamine suppliers and proper testing are critical for successful cell culture.