Home Technical Information Amino Acids Phenylalanine
Phenylalanine (symbol Phe or F) is an essential α-amino acid with the molecular formula C9H11NO2. It can be considered as a substitution of a benzyl group for the methyl group of alanine or a phenyl group instead of a terminal hydrogen of alanine. This essential amino acid is classified as neutral and nonpolar due to the inert and hydrophobic nature of its benzyl side chain. Phenylalanine serves as a precursor for various important molecules, including tyrosine, as well as the monoamine neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), and the skin pigment melanin. It occurs naturally in the milk of mammals and is utilized in the production of food and beverages. Phenylalanine is also available as a nutritional supplement, known for its analgesic and antidepressant effects. It directly contributes to the formation of the neuromodulator phenethylamine, a commonly used dietary supplement. In humans and other animals, phenylalanine is considered an essential amino acid as it is not synthesized de novo, and must be obtained through dietary sources or phenylalanine-containing proteins. The codons UUU and UUC encode phenylalanine.
Structure | ![]() |
CAS Number | 63-91-2 |
Classification |
Hydrophobic amino acids (nonpolar amino acids), including |
Categories |
Phenylalanine Biosynthesis Related Compounds | |
617-12-9 | Chorismate |
126-49-8 | Prephenate |
53078-86-7 | L-Arogenate |
63-91-2 | L-Phenylalanine |