isoleucine

noun

iso·​leu·​cine ˌī-sō-ˈlü-ˌsēn How to pronounce isoleucine (audio)
: a crystalline, hydrophobic, essential amino acid C6H13NO2 that is obtained in its levorotatory l-form by the hydrolysis of dietary protein and is isomeric with leucine

Examples of isoleucine in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
This means there is twice as much leucine as there is isoleucine or valine. — Lindsay Curtis, Verywell Health, 25 Jan. 2026 BCAAs are three amino acids—leucine, isoleucine, and valine—that aren't naturally made in the body. — Health, 17 June 2025 Three specific essential amino acids—leucine, isoleucine, and valine—are called Branched-Chain Amino Acids. — Shimite Obialo, Forbes.com, 26 May 2026 But that does indicate that 17 of them got by ok without isoleucine, including one where it was swapped out in 45 different positions along the amino acid chain. — ArsTechnica, 30 Apr. 2026 See All Example Sentences for isoleucine

Word History

Etymology

International Scientific Vocabulary

First Known Use

1903, in the meaning defined above

Time Traveler
The first known use of isoleucine was in 1903

Rhymes for isoleucine

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Browse Nearby Words

Isolde
isoleucine
isoline
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Cite this Entry

“Isoleucine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/isoleucine. Accessed 7 Jul. 2026.

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Medical Definition

isoleucine

noun
iso·​leu·​cine ˌī-sō-ˈlü-ˌsēn How to pronounce isoleucine (audio)
: a crystalline essential amino acid C6H13NO2 isomeric with leucine
—abbreviation Ile

More from Merriam-Webster on isoleucine

Britannica.com: Encyclopedia article about isoleucine

Last Updated: - Updated example sentences
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