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

Compare meaning

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

• isoleucine vs. leucine

Example Sentences

See Examples For:

leucine

While leucine is already known for its role in building proteins, the new research uncovered another important function.

From Science Daily ● May 21, 2026

The team also examined human lung cancer cells and discovered that some cancer related mutations affecting leucine metabolism appeared to improve cancer cell survival.

From Science Daily ● May 21, 2026

To better understand the broader impact of the discovery, the researchers studied the effects of leucine metabolism in the tiny roundworm Caenorhabditis elegans.

From Science Daily ● May 21, 2026

By uncovering how leucine regulates mitochondrial activity, the researchers believe their work could eventually help guide new treatments for metabolic disorders, cancer, and other diseases linked to impaired energy production.

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 Thatcher, Roscoe Wilfred