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white to light beige fine crystalline powder

S-Methyl-L-cysteine is a substrate in the catalytic antioxidant system mediated by methionine sulfoxide reductase A (MSRA). It has been studied as a theurapeutic for neurodegenerative diseases including Parkinson′s.

ChEBI: A cysteine derivative that is L-cysteine in which the hydrogen attached to the sulfur is replaced by a methyl group.

Likely impurities are cysteine and S-methyl-dl-cysteine. Crystallise it from H2O by adding 4volumes of EtOH. It also crystallises from MeOH with m 234-236o(dec), but after sublimation i t has m 267-270o and [] 27D -31.6o (c 1, H2O). [Rinderknecht et al. Helv Chim Acta 41 1, 10 1958, Theodoropoulos Acta Chem Scand 13 383 1959, Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 p 1904 1961, Beilstein 4 IV 3145.]