leucine

American  

[loo-seen, -sin] / ˈlu sin, -sɪn /

noun

Biochemistry.

1. a white, crystalline, water-soluble amino acid, C 6 H 13 NO 2 , obtained by the decomposition of proteins and made synthetically: essential in the nutrition of humans and animals. Leu; L

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leucine British  

/ ˈluːsɪn, ˈluːsiːn /

noun

1. an essential amino acid found in many proteins

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leucine Scientific  

/ lo̅o̅′sēn′ /

1. An essential amino acid. Chemical formula: C ₆ H ₁₃ NO ₂ .

2. See more at amino acid

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Etymology

Origin of leucine

First recorded in 1820–30; leuc- + -ine ¹

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Compare meaning

How does leucine compare to similar and commonly confused words? Explore the most common comparisons:

• isoleucine vs. leucine

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Example Sentences

See Examples For:

leucine

By revealing this previously unknown link between leucine, protein quality control, and mitochondrial metabolism, the researchers have identified potential new targets for diseases in which cellular energy production is disrupted, including cancer and metabolic disorders.

From Science Daily ● Oct. 3, 2026

In the worms, problems with leucine breakdown disrupted mitochondrial function and were linked to fertility problems.

From Science Daily ● Oct. 3, 2026

According to the researchers, leucine appears to reduce the activity of SEL1L.

From Science Daily ● Oct. 3, 2026

"We were thrilled to discover that a cell's nutrient status, especially its leucine levels, directly impacts energy production," said Dr. Qiaochu Li, first author of the study.

From Science Daily ● May 21, 2026

Hydrolysis by acids indicates that it contains leucine and tyrosine, two amino-acids which are constituents of proteins, along with other bodies of unknown composition.

From The Chemistry of Plant Life by Roscoe Wilfred Thatcher

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