methionine

 
Pronunciation: /mɪˈθʌɪəniːn/

noun

[mass noun] Biochemistry
  • a sulphur-containing amino acid which is a constituent of most proteins and is essential to the diet of vertebrates.
    • Chemical formula: CH3S(CH2)2CH(NH2)COOH

Origin:

1920s: from methyl + Greek theion 'sulphur'