Definition of methionine in English:


Line breaks: me¦thio|nine
Pronunciation: /mɪˈθʌɪəniːn


[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
    More example sentences
    • They fix nitrogen and so contain high quality protein, including the essential amino acids methionine and cystine.
    • The oxidation sites of alpha-crystallin are considered to be methionine, cysteine and tryptophan amino acid residues.
    • For example, eggs are high in alanine and methionine; whey protein is high in tryptophan and threonine.


1920s: from methyl + Greek theion 'sulphur'.

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Pronunciation: grəʊˈtɛskəri
grotesque quality or grotesque things collectively