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L-Methionine sulfoximine

Linear Formula:
CAS Number:
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PubChem Substance ID:

Quality Level


cell based assay: suitable


>210 °C (dec.) (lit.)


suitable for molecular biology

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L-Methionine sulfoximine has been used as a potent inhibitor of glutamine synthetase (GS) activityto study its effect on the lifespan and disease progression in the SOD1 G93A mouse model for amyotrophic lateral sclerosis.

Use of high levels of MSX can enhance productivity and production stability in multiple recombinant GS CHO cell lines and GS–CHOK1SV cell lines without compromising product quality. These findings have important implications for improving the efficiency and reliability of industrial cell culture processes used in the production of biologics.

MSX, a potent convulsant, has shown a specific and significant impact on glutamine dynamics in primary cortical astrocyte cultures. This makes it a valuable compound for studying and modulating glutamine-related processes in cell culture.

Biochem/physiol Actions

As a potent inhibitor of glutamine synthetase activity (GS), this reagent has widely been used as a selection agent for plasmid integration in Chinese hamster ovary (CHO) and other mammalian cell lines. The growing demand for high yield cell banks for production of recombinant proteins for therapeutics has resulted in two major systems for selection of stable and active clones, Methotrexate selection of dihydrofolate reductase (DHFR) overexpressing cells and MSX selection of glutamine synthetase overexpressing cells. Cells are grown in the absence of glutamine in the media and inhibition of the endogenous activity of glutamine synthetase results in cell death for cells lacking overexpression. The MSX-glutamine synthetase selection mechanism provides benefits over that of the Methotrexate-DHFR system in that it typically requires a single amplification step and results in significant reduction of time to produce high stability, highly amplified clones. L-Methionine sulfoximine (MSX) enhances NH3 production in seedling leaves wheat, barley, corn and sorghum plants by inhibiting GS activity. MSX increases ornithine decarboxylase activity and decreases the survival rate in a model of transient cerebral ischemia.


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Hazard Statements

Hazard Classifications

Eye Irrit. 2 - Skin Irrit. 2 - STOT SE 3

Target Organs

Respiratory system

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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