phenylalanine

American

[fen-l-al-uh-neen, -nin, feen-] / ˌfɛn lˈæl əˌnin, -nɪn, ˌfin- /

noun

Biochemistry.

a crystalline, water-soluble, essential amino acid, C 6 H 5 CH 2 CH(NH2 )COOH, necessary to the nutrition of humans and most animals, obtained chiefly from egg white or skim milk. Phe; F

phenylalanine British

/ ˌfiːnaɪlˈæləˌniːn, ˌfɛnɪl- /

noun

an aromatic essential amino acid; a component of proteins

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

phenylalanine Scientific

/ fĕn′əl-ăl′ə-nēn′ /

An essential amino acid. Chemical formula: C ₉ H ₁₁ NO ₂ .
See more at amino acid

Etymology

Origin of phenylalanine

First recorded in 1880–85; phenyl + alanine

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The connection remained even after accounting for other related factors, including phenylalanine.

From Science Daily • Feb. 26, 2026

They used both observational data and genetic techniques to assess whether blood levels of phenylalanine and tyrosine were related to overall mortality and predicted lifespan.

From Science Daily • Feb. 26, 2026

People with PKU cannot break down phenylalanine, an amino acid found in protein foods.

From BBC • Jan. 1, 2024

These metabolites include phenylalanine, aspartic acid and methanol.

From Salon • Jul. 14, 2023

The person must closely follow a strict diet that is low in phenylalanine to avoid symptoms and damage.

From Textbooks • Jun. 19, 2013

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023