Tyrosine

Tyrosine
	Skeletal formula of L-tyrosine
	L-Tyrosine at physiological pH
ball-and-stick model	space-filling model
Names
	IUPAC name Tyrosine
	Systematic IUPAC name 2-Amino-3-(4-hydroxyphenyl)propanoic acid
Identifiers
CAS Number	60-18-4 (L) ;
3D model (JSmol)	Interactive image; Zwitterion: Interactive image;
ChEBI	CHEBI:17895 ;
ChEMBL	ChEMBL925 ;
ChemSpider	5833 ;
DrugBank	DB00135 ;
ECHA InfoCard	100.000.419
IUPHAR/BPS	4791;
KEGG	C00082;
PubChem CID	6057;
UNII	42HK56048U ;
CompTox Dashboard (EPA)	DTXSID1023730 ;
	InChI InChI=1S/C9H11NO3/c10-8(9(12)13)5-6-1-3-7(11)4-2-6/h1-4,8,11H,5,10H2,(H,12,13)/t8-/m0/s1 Key: OUYCCCASQSFEME-QMMMGPOBSA-N ; Key: OUYCCCASQSFEME-UHFFFAOYSA-N; Key: OUYCCCASQSFEME-MRVPVSSYSA-N;
	SMILES N[C@@H](Cc1ccc(O)cc1)C(O)=O; Zwitterion: [NH3+][C@@H](Cc1ccc(O)cc1)C([O-])=O;
Properties
Chemical formula	C9H11NO3
Molar mass	181.191 g·mol−1
Appearance	white solid
Solubility in water	45.3 mg/100 mL
Magnetic susceptibility (χ)	−105.3·10−6 cm3/mol
Hazards
NFPA 704 (fire diamond)	1 1 0
Supplementary data page
	Tyrosine (data page)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

L-Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a conditionally essential amino acid with a polar side group. The word "tyrosine" is from the Greek tyrós, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese. It is called tyrosyl when referred to as a functional group or side chain. While tyrosine is generally classified as a hydrophobic amino acid, it is more hydrophilic than phenylalanine. It is encoded by the codons UAC and UAU in messenger RNA.

The one-letter symbol Y was assigned to tyrosine for being alphabetically nearest of those letters available. Note that T was assigned to the structurally simpler threonine, U was avoided for its similarity with V for valine, W was assigned to tryptophan, while X was reserved for undetermined or atypical amino acids. The mnemonic tYrosine was also proposed.