methionine

noun2

1. •
   A sulphur-containing amino acid, C₅H₁₁NO₂S, in L- and D-forms.
2. •
   The L-form thereof, a lipotropic molecule widely occurring in living organisms and found in most protein; in humans it is an essential amino acid.

   • The purpose was to make soya beans more healthy for those for whom they are a staple food by correcting soya beans' natural deficiency in a chemical called methionine. — 1999