... : C5H11NO2S Molecule Weight: 149.21 Manufacture Standards: AJI92,USP26,EP4 L-MethionineIndications and UsageMethionine (abbreviated as Met or M) is an ... donor. Methionine is an intermediate in the biosynthesis of cysteine, carnitine, taurine, lecithin, phosphatidylcholine, and other phospholipids. Improper conversion of methionine ...