amino acid


Definition of amino acid

: an amphoteric organic acid containing the amino group NH2 especially : any of the various amino acids having the amino group in the alpha position that are the chief components of proteins and are synthesized by living cells or are obtained as essential components of the diet

Examples of amino acid in a Sentence

Recent Examples on the Web Salmon also includes an amino acid called tryptophan, Gans says. Maggie O'neill,, "13 Salmon Benefits, According to Nutritionists," 22 Feb. 2021 The mutation is denominated E484K, meaning that the amino acid, glutamic acid (code letter E), has been replaced by another, lysine (code letter K), in position 484 of the genetic sequence of the spike protein. Lawrence Wright, The New Yorker, "Can the COVID-19 Vaccine Beat the Proliferation of New Virus Mutations?," 21 Jan. 2021 Each bead would represent an amino acid, which are smaller molecules containing carbon, oxygen, hydrogen and sometimes sulfur atoms. Nathan Ahlgren, The Conversation, "What is a protein? A biologist explains," 13 Jan. 2021 Tryptophan is an amino acid found in many foods, including dairy and turkey. Star Tribune, "How foods may affect our sleep," 8 Jan. 2021 Sequences showed that virus had accumulated a slew of mutations that together caused 17 amino acid changes in the virus’ proteins, eight of them in the crucial spike protein. Kai Kupferschmidt, Science | AAAS, "U.K. variant puts spotlight on immunocompromised patients’ role in the COVID-19 pandemic," 23 Dec. 2020 The 2018 AlphaFold was a collection of parts: one neural network predicted the distance between amino acid pairs in a protein, another tried to determine the most likely angles between them, and a third piece refined the overall structure. Jeremy Kahn, Fortune, "Lessons from DeepMind’s breakthrough in protein-folding A.I.," 1 Dec. 2020 These can be charged or neutral, acidic or basic, etc., and these properties determine how each amino acid interacts with its neighbors and the environment. John Timmer, Ars Technica, "DeepMind AI handles protein folding, which humbled previous software," 30 Nov. 2020 Peptides are an amino acid used by your skin to build collagen and elastin, which means that serums containing the ingredient can help skin appear firmer. Sarah Midkiff,, "Hailey Bieber Just Shared Her Entire Winter Skincare Routine," 7 Dec. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'amino acid.' 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 amino acid

1897, in the meaning defined above

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Time Traveler for amino acid

Time Traveler

The first known use of amino acid was in 1897

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Statistics for amino acid

Last Updated

28 Feb 2021

Cite this Entry

“Amino acid.” Dictionary, Merriam-Webster, Accessed 2 Mar. 2021.

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More Definitions for amino acid

amino acid


English Language Learners Definition of amino acid

biology : any one of many acids that occur naturally in living things and that include some which form proteins

amino acid

ami·​no acid | \ ə-ˈmē-nō- \

Kids Definition of amino acid

: any of various acids containing carbon and nitrogen that are building blocks of protein and are made by living plant or animal cells or are obtained from the diet

amino acid


Medical Definition of amino acid

: an amphoteric organic acid containing the amino group NH2 especially : alpha-amino acid

More from Merriam-Webster on amino acid

Nglish: Translation of amino acid for Spanish Speakers Encyclopedia article about amino acid

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