5-Methylcysteine sulphoxide

Several polysulphides occur in hop oil. Dimethyl trisulphide (2,3,4-trithiapentane) occurs only in oil prepared from hops which have not been treated with sulphur (dioxide) on the kiln. It is absent from oil prepared by vacuum distillation at 25°C but is formed at lOO C from the precursor 5-methylcysteine sulphoxide (CH3SO-CH2CH(NH2)COOH). This precursor is destroyed by sulphur dioxide when sulphur is burnt in the oast but is slowly regenerated on storage. Dimethyl tetrasulphide and 2,3,5-trithiahexane are... 

Forage brassicas may also cause a haemolytic anaemia in mminants, in extreme cases of which the haemoglobin content of the blood falls to only one-third of its normal value and the red cells are destroyed so rapidly that haemoglobin appears in the mine (haemoglobinuria).The condition is due to the presence in brassicas of the unusual amino add S-methylcysteine sulphoxide, which in the mmen is reduced to dimethyl disulphide ... 

The dimethyl disulphide is known to damage the red cells. Green brassicas contain 10 20 g S-methylcysteine sulphoxide per kilogram of DM. The condition is... 

Other forage crops include immature cereals, sugarcane (and its fibrous by-product bagasse), various brassica species and the green tops of root crops. Brassicas such as kale contain goitrogens and also the unusual amino acid S-methylcysteine sulphoxide, which causes haemolytic anaemia in ruminants. 

Stereospecific S-oxidation to the sulphoxide has been observed in Allium cepa with S-methylcysteine, S-ethylcysteine, S-propylcysteine, S-trans-prop-enylcysteine, S-cis-propenylcysteine, and deoxycycloallinin as the sulphidic precursors. ... 

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