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‘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.’
- ‘Contents of glutamine, asparagine, methionine, and tryptophan in the tissues were not determined by this method.’
- ‘Homocysteine is an intermediary metabolite of essential dietary amino acid methionine.’
1920s from methyl + Greek theion ‘sulphur’.
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