GSEM Supplement, 50X Liquid

The Glutamine Synthetase Expression Medium (GSEM) with supplement is a system that supports the growth of transfected cells containing the gene for the enzyme Glutamine synthetase. L-Glutamine is a vital amino acid that is required by the cells as a source of nitrogen for the synthesis of other amino acids as well as nucleotides (purines). It can also be used as a source of energy in glucose-deficient conditions. If the medium is glutamine-deficient, cells require the enzyme Glutamine synthetase (GS) and GSEM supplement for the biosynthesis of glutamine from glutamate and ammonia. Certain cell lines, such as the mouse myeloma cell line NS0, do not express GS. These cells can survive in glutaminedeficient media only when they are transfected with the GS gene. Other cell lines, such as CHO cells, express sufficient GS to survive in glutamine-deficient media. In case of transfected CHO cells, GS inhibitor methionine sulphoximine (MSX) is used to inhibit endogenous GS activity such that only transfectants with additional GS activity can survive. These two cell lines (NS0 and CHO) are widely used for the industrial production of antibodies. The gene of interest is integrated in an expression vector which also contains GS gene in the presence of GSEM supplement. When grown in glutamine-deficient media, only those cells having the GS gene (and therefore the product gene) survive. CHO cells are grown in glutamine-deficient medium containing MSX. This system generates high-yielding cell lines in a reduced time span. TCL088 is sterile-filtered, 50X liquid Glutamine Synthetase Expression Medium Supplement. TCL088 is sterile-filtered, 50X liquid Glutamine Synthetase Expression Medium Supplement.