me·​thi·​o·​nine | \ mə-ˈthī-ə-ˌnēn \

Definition of methionine

: a crystalline sulfur-containing essential amino acid C5H11NO2S that occurs in the levorotatory form as a constituent of many proteins

Examples of methionine in a Sentence

Recent Examples on the Web

Plants use sulfur to manufacture cysteine and methionine, two amino acids important for producing protein. Patrick Di Justo, WIRED, "What's Inside Sta-Green Planting Mix? Masterful Decomposition.," 28 July 2010

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'methionine.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of methionine

1928, in the meaning defined above

History and Etymology for methionine

International Scientific Vocabulary, from methyl + thion- + -ine entry 2

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The first known use of methionine was in 1928

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me·​thi·​o·​nine | \ mə-ˈthī-ə-ˌnēn \

Medical Definition of methionine

: a crystalline sulfur-containing essential amino acid C5H11NO2S that occurs in the L-form as a constituent of many proteins (as casein and egg albumin), that is important especially as a source of sulfur for the biosynthesis of cysteine and as a source of methyl groups for transmethylation reactions (as in the biosynthesis of choline, creatine, and adrenaline), and that is used as a dietary supplement for human beings and their domestic mammals and poultry and in the treatment of fatty infiltration of the liver abbreviation Met

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