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L-Alanin - L-Alanine.svg
IUPAC name Alanine
Other names 2-Aminopropanoic acid
CAS number 338-69-2
PubChem 5950
KEGG C01401
Molecular formula C3H7NO2
Molar mass 89.08 g mol-1
Appearance white powder
Density 1.424 g/cm3
Melting point

258 °C, 531 K, 496 °F

Solubility in water 167.2 g/L (25 °C)
log P -0.68[1]
Acidity (pKa)
  • 2.34 (carboxyl; H2O)
  • 9.87 (amino; H2O)[2]
-50.5·10−6 cm3/mol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Alanine (abbreviated as Ala or A)[3] is an α-amino acid. It has the chemical formula CH3CH(NH2)COOH.

The L-isomer is one of the 20 amino acids encoded by the genetic code. Its codons are GCU, GCC, GCA, and GCG. It is classified as a non-polar amino acid.[4]

L-Alanine accounts for 7.8% of the primary structure in a sample of 1,150 proteins.[5][6] Leucine is the only amino acid which is more common.

D-Alanine occurs in bacterial cell walls and in some peptide antibiotics.


  1. "L-alanine_msds". 
  2. Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. p. 5–88. ISBN 978-1498754286 . 
  3. Nomenclature and symbolism for amino acids and peptides. IUPAC-IUB Recommendations 1983. Pure Appl. Chem. 56 (5), 1984: 595–624.
  4. Non-polar: electrons shared so that there is no difference in electric charge between different parts of the molecule.
  5. Doolittle, R. F. (1989), "Redundancies in protein sequences", in Fasman, G. D., Prediction of protein structures and the principles of protein conformation, New York: Plenum, pp. 599–623, ISBN 0-306-43131-9  
  6. Primary structure: the exact specification of its atomic structure and its chemical bonds.