me·​thi·​o·​nine mə-ˈthī-ə-ˌnēn How to pronounce methionine (audio)
: 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 Creatine Monohydrate Creatine monohydrate is a combination of three different amino acids: methionine, arginine, and glycine. Douglas Maroney, Discover Magazine, 7 Jan. 2024 Made from split peas, pea protein ($21, Amazon) contains all of the essential amino acids, but is low in one—methionine. Brierley Horton, Ms, Better Homes & Gardens, 14 Jan. 2024 Quercetin is ideal to treat joint inflammation and autoimmune diseases like arthritis, while methionine boosts cell metabolism, prevents inflammation, and treats conditions like arthritis and fibromyalgia, especially when combined with glucosamine (14)(15). Discover Magazine, 29 Mar. 2023 High-quality protein is any protein that contains all of the nine essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine) that our bodies don’t make on their own. USA TODAY, 2 July 2023 Price at time of publication: $40 for 90 count ($0.44 per serving) Key Specs Form: Caplet | Dose: 400 mg | Active Ingredients: S-adenosyl methionine | Servings Per Container: 60 A Word of Caution on SAMe Just like medications, supplements can come with side effects. Sarah Anzlovar, Ms, Verywell Health, 15 May 2023 Vitapost ProJoint Plus Vitapost ProJoint Plus is marketed as a premium joint support supplement with a formula that consists of glucosamine sulphate, boswellia serrata extract, chondroitin sulfate, turmeric, quercetin, methionine, MSM, and bromelain. Discover Magazine, 29 Mar. 2023 Common side effects tend to be related to the digestive system.110 Plus, information about feverfew is similar to devil's claw regarding use while pregnant or breastfeeding.310 S-adenosyl methionine (SAMe): One of SAMe's potential use is osteoarthritis. Verywell Health, 21 Feb. 2023 This codon specifies the amino acid methionine. William A. Haseltine, Forbes, 30 Aug. 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'methionine.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

First Known Use

1928, in the meaning defined above

Time Traveler
The first known use of methionine was in 1928

Dictionary Entries Near methionine

Cite this Entry

“Methionine.” Dictionary, Merriam-Webster, Accessed 19 Jul. 2024.

Medical Definition


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