Title: Tyrosine
CAS Registry Number: 60-18-4
CAS Name: L-Tyrosine
Additional Names: Tyr; Y; b-(p-hydroxyphenyl)alanine; a-amino-p-hydroxyhydrocinnamic acid; (S)-a-amino-4-hydroxybenzenepropanoic acid
Molecular Formula: C9H11NO3
Molecular Weight: 181.19
Percent Composition: C 59.66%, H 6.12%, N 7.73%, O 26.49%
Literature References: Non-essential amino acid for human development; precursor for the synthesis of thyroid hormones and select neurotransmitters, such as dopamine and norepinephrine. May be considered essential by the brain. Name derived from the Greek "tyros" for "cheese" from which it was first identified and isolated: J. Liebig, Ann. 57, 127 (1846); idem, ibid. 62, 257 (1847). Early chemistry and biochemistry: Amino Acids and Proteins, D. M. Greenberg, Ed. (Charles C. Thomas, Springfield, IL, 1951) 950 pp., passim; J. P. Greenstein, M. Winitz, Chemistry of the Amino Acids vol 1-3 (John Wiley and Sons, Inc., New York, 1961) pp. 2348-2367, passim. Synthesis of labeled form: Y. Watanabe et al., Acta Radiol. 376 (Suppl.), 110 (1991). Intrinsic fluorophore in proteins; used in characterizing structure and conformational changes: V. Giancotti et al., Biochim. Biophys. Acta 624, 60 (1980); S. T. Ferreira et al., Biophys. J. 66, 1185 (1994); B. Kierdaszuk et al., Photochem. Photobiol. 61, 319 (1995). Review of determn in blood: E. Robins, Methods Biochem. Anal. 17, 287-309 (1969). Review of neurotransmitter synthesis: C. J. Gibson, Retina 2, 332-340 (1982). Review of toxicity: C. Laberge et al., Adv. Exp. Med. Biol. 206, 209-221 (1986). Review of post-translational phosphorylation: S. Atherton-Fessler et al., Semin. Cell Biol. 4, 433-442 (1993); sulfation: C. Niehrs et al., Chem. Biol. Interact. 92, 257-271 (1994).
Properties: Fine silky needles, dec 342-344° (closed capillary, bath preheated to 280°, rapid heating). d 1.456. pK1 2.20; pK2 9.11; pK3 10.07. [a]D22 -10.6° (c = 4 in HCl); [a]D18 -13.2° (c = 4 in 3N NaOH). Soly in water (g/100 g): 0.02 at 0°; 0.045 at 25°; 0.105 at 50°; 0.244 at 75°; 0.565 at 100°. Insol in common neutral solvents, such as abs alcohol, ether, acetone, except water. Sol in alkaline solns.
pKa: pK1 2.20; pK2 9.11; pK3 10.07
Optical Rotation: [a]D22 -10.6° (c = 4 in HCl); [a]D18 -13.2° (c = 4 in 3N NaOH)
Density: d 1.456
Derivative Type: DL-Form
Properties: Synthetic product. Stout needles. Dec 316°. Soly in water (g/100 g): 0.0147 at 0°; 0.351 at 25°; 0.0836 at 50°.
Derivative Type: D-Form
Properties: Crystals. Dec 310-314°. [a]D25 +10.3° (c = 4 in HCl). Soly in water (g/100 g): 0.196 at 0°; 0.1052 at 50°.
Optical Rotation: [a]D25 +10.3° (c = 4 in HCl)
Use: Probe for studying protein structure and dynamics.
Tyrothricin Yam, Mexican Yellow AB Yellow OB Yingzhaosu

Skeletal formula of the L-isomer
Ball-and-stick model of the L-isomer as a zwitterion
CAS number 60-18-4 (L) YesY
PubChem 1153
ChemSpider 5833 YesY
DrugBank DB03839
Jmol-3D images Image 1
Molecular formula C9H11NO3
Molar mass 181.19 g mol−1
MSDS External MSDS
NFPA 704
NFPA 704.svg
Supplementary data page
Structure and
n, εr, etc.
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Tyrosine (abbreviated as Tyr or Y)[1] or 4-hydroxyphenylalanine, is one of the 22 amino acids that are used by cells to synthesize proteins. Its codons are UAC and UAU. It is a non-essential amino acid with a polar side group. The word "tyrosine" is from the Greek tyros, meaning cheese, as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese.[2][3] It is called tyrosyl when referred to as a functional group or side chain.