D-methionine sulfoxide hydrochloride, the D-isomer of methionine sulfoxide hydrochloride, is the oxidation product of methionine. Methionine is a restrictive amino acid in milk or legume proteins and is easily oxidized during storage.
Methionine sulfoximine (MSO) is an irreversible glutamine synthetase inhibitor. It is the sulfoximine derivative of methionine with convulsant effects.