tyrosine

American  

[tahy-ruh-seen, -sin, tir-uh-] / ˈtaɪ rəˌsin, -sɪn, ˈtɪr ə- /

noun

Biochemistry.

1. a crystalline amino acid, HOC 6 H 4 CH 2 CH(NH2 )COOH, abundant in ripe cheese, that acts as a precursor of norepinephrine and dopamine. Tyr; Y

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tyrosine British  

/ -sɪn, ˈtɪrə-, ˈtaɪrəˌsiːn /

noun

1. an aromatic nonessential amino acid; a component of proteins. It is a metabolic precursor of thyroxine, the pigment melanin, and other biologically important compounds

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tyrosine Scientific  

/ tī′rə-sēn′ /

1. A nonessential amino acid. Chemical formula: C ₉ H ₁₁ NO ₃ .

2. See more at amino acid

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Etymology

Origin of tyrosine

1855–60; < Greek tȳrós cheese + -ine ²

Example Sentences

Approaches such as moderating overall protein intake could potentially lower tyrosine levels and support healthier aging.

From Science Daily • Feb. 26, 2026

Researchers also noted that men generally have higher tyrosine levels than women, which may help explain part of the longstanding lifespan gap between the sexes.

From Science Daily • Feb. 26, 2026

However, after deeper analysis, only tyrosine showed a consistent and potentially causal relationship with reduced life expectancy in men.

From Science Daily • Feb. 26, 2026

"Phenylalanine showed no association with lifespan in either men or women after controlling for tyrosine."

From Science Daily • Feb. 26, 2026

It is also found in horse’s liver, being one of the putrefaction products of tyrosine.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 6 "Coucy-le-Château" to "Crocodile" by Various