Stability of L-glutamine in liquid media
L-glutamine is not stable in dissolved form, if stored at +2 - +8 °C, or higher temperatures. Due to cyclisation of L-glutamine, toxic NH3 is formed. Cell culture media containing L-glutamine and L-glutamine itself must, therefore, be stored at -20 °C.
As a substitute for L-glutamine, which limits the shelf life of media, dipeptides containing L-glutamine can be used as a source. These dipeptides have a prolonged stablility, even at room temperature. Cells can readily metabolize it into L-glutamine by cleaving the inherent peptide binding. L-alanyl-L-glutamine (Ala-Gln) or Glycyl-L-glutamine (Gly-Gln) are generally being used in media as a source.
to L-alanyl-L-glutamine (Ala-Gln)
Biochrom GmbH offers the most common cell culture media in a version containing Ala-Gln as “stable glutamine” (cat. no. with FG ...). From the experience, the cells in the FG-media mostly show the same, and partly, even a better growth.