Methionine sulfoximine

Methionine sulfoximine (MSO, also known as MetSox^[1]) is an irreversible glutamine synthetase inhibitor. It is the sulfoximine derivative of methionine with convulsant effects.^[2]

l-Methionine sulfoximine

Names
IUPAC name (2S)-2-Amino-4-(S-methylsulfonimidoyl)butanoic acid
Other names l-Methionine sulfoximine; MSO
Identifiers
CAS Number	15985-39-4 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1725509
ChEBI	CHEBI:28490
ChemSpider	80339
ECHA InfoCard	100.016.224
EC Number	217-845-8
PubChem CID	89034
UNII	M9P6YZ6JX9 Y
CompTox Dashboard (EPA)	DTXSID201031266
InChI InChI=1S/C5H12N2O3S/c1-11(7,10)3-2-4(6)5(8)9/h4,7H,2-3,6H2,1H3,(H,8,9)/t4-,11?/m0/s1 Key: SXTAYKAGBXMACB-DPVSGNNYSA-N
SMILES CS(=N)(=O)CC[C@@H](C(=O)O)N
Properties
Chemical formula	C5H12N2O3S
Molar mass	180.22 g·mol−1
Related compounds
Related compounds	Buthionine sulfoximine Glufosinate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Methionine sulfoximine is composed of two different diastereomers, which are L-S-Methionine sulfoximine and L-R-Methionine sulfoximine. These affect the longevity of the model mouse for Lou Gehrig's disease.^[3] Overproduction of glutamate results to excitotoxicity, which kills the cell. Since methionine sulfoximine inhibits glutamate production in the brain, it prevents excitotoxicity. Thus, increasing the longevity of the mice.^[4]

Mechanism of action

MSO is phosphorylated by glutamine synthetase. The resulting product acts as a transition state analog that is unable to diffuse from the active site, thereby inhibiting the enzyme.^[5]

Phosphorylation of MSO by glutamine synthetase