methionine

noun
me·​thi·​o·​nine | \ mə-ˈthī-ə-ˌnēn How to pronounce methionine (audio) \

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 The culprit is methionine, an amino acid that contains sulfur. Esther Mobley, SFChronicle.com, "Wine’s asparagus conundrum," 7 May 2020 In the search for another path to the fountain of youth, researchers have been exploring the role of methionine and cysteine, two of the body's nine essential amino acids which contain sulfur. Sandee Lamotte, CNN, "Heard of the low sulfur diet? Eating low-protein may prolong your life, say researchers," 3 Feb. 2020 In one early study of rats, limiting methionine by 80% increased the rats' lifespans by an average of 43%. Sandee Lamotte, CNN, "Heard of the low sulfur diet? Eating low-protein may prolong your life, say researchers," 3 Feb. 2020 For example, grains are low in lysine, while beans and nuts are low in methionine, the FDA says. Carolyn L. Todd, SELF, "Does It Make a Difference if You Get Your Protein from Plants or Animals?," 28 Aug. 2019 For instance, grains are low in an amino acid called lysine, while beans and nuts are low in methionine. Carolyn L. Todd, SELF, "Here's What Actually Happens in Your Body When You Eat Protein," 20 June 2019 More specifically, methylenetetrahydrofolate reductase converts the amino acid homocysteine to another, methionine. Tara C. Smith, SELF, "Why You Don't Actually Need to Test for MTHFR Gene Variants," 18 Mar. 2019 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.

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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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Time Traveler for methionine

Time Traveler

The first known use of methionine was in 1928

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Cite this Entry

“Methionine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/methionine. Accessed 18 Jan. 2021.

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More Definitions for methionine

methionine

noun
me·​thi·​o·​nine | \ mə-ˈthī-ə-ˌnēn How to pronounce methionine (audio) \

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

More from Merriam-Webster on methionine

Britannica.com: Encyclopedia article about methionine

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