leu·​cine | \ ˈlü-ˌsēn How to pronounce leucine (audio) \

Definition of leucine

: a white crystalline essential amino acid C6H13NO2 that is obtained by the hydrolysis of dietary protein (as of eggs, soy, or fish) and plays an important role in various physiological functions (as the regulation of insulin secretion and stimulation of protein synthesis in skeletal muscle)

Examples of leucine in a Sentence

Recent Examples on the Web Studies done on supplements like leucine, which some early research suggested could kickstart the muscle-building process inside cells, haven’t panned out. Sara Chodosh, Popular Science, "There are only two supplements proven to help you build muscle," 3 Jan. 2019 Animal proteins are also higher than plant proteins in one particular amino acid, leucine, which is thought to be key to muscle protein synthesis. Carolyn L. Todd, SELF, "Does It Make a Difference if You Get Your Protein from Plants or Animals?," 28 Aug. 2019

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

First Known Use of leucine

1826, in the meaning defined above

History and Etymology for leucine

French, from leuc- leuk-

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Time Traveler for leucine

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The first known use of leucine was in 1826

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Cite this Entry

“Leucine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/leucine. Accessed 15 Aug. 2020.

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More Definitions for leucine


leu·​cine | \ ˈlü-ˌsēn How to pronounce leucine (audio) \

Medical Definition of leucine

: a white crystalline essential amino acid C6H13NO2 obtained by the hydrolysis of most dietary proteins abbreviation Leu

More from Merriam-Webster on leucine

Britannica.com: Encyclopedia article about leucine

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