Title: Alanine
CAS Registry Number: 56-41-7
CAS Name: L-Alanine
Additional Names: Ala; A; L-a-alanine; L-a-aminopropionic acid; (S)-2-aminopropanoic acid
Molecular Formula: C3H7NO2
Molecular Weight: 89.09
Percent Composition: C 40.44%, H 7.92%, N 15.72%, O 35.92%
Literature References: Non-essential amino acid for human development. First syllable of the name denotes its origin from aldehyde. First synthesized and named by: A. Strecker, Ann. 75, 27 (1850); prior to identification in silk hydrolysate: P. Schützenberger, A. Bourgeous, Compt. Rend. 81, 191 (1875); Th. Weyl, Ber. 21, 1407 (1888). 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 vols 1-3 (John Wiley and Sons, Inc., New York, 1961) pp. 1819-1840, passim. Enantiomeric selective synthesis: R. Amoroso et al., J. Org. Chem. 57, 1082 (1992). Review of metabolism in man: J. E. Liljenquist et al., Clin. Nutr. Update, H. L. Greene et al., Eds. (American Medical Association, Chicago, IL, 1977) pp 22-34; T. N. Palmer et al., Biosci. Rep. 5, 1015-1033 (1985). Review of industrial production by microorganisms: S. Takamatsu, T. Tosa, Bioprocess Technol. 16, 25-35 (1993).
Properties: Orthorhombic crystals from water, dec 297°. d 1.401. [a]D25 +2.42° (c = 10 in H2O); +13.7° (c = 2.06 in 6N HCl). pK1 2.34; pK2 9.69. Soly (g/l) in water at 0°: 127.3; at 25°: 166.5; at 50°: 217.9; at 75°: 285.1; at 100°: 373.0. Soly in cold 80% ethanol: 0.2%. Insol in ether.
pKa: pK1 2.34; pK2 9.69
Optical Rotation: [a]D25 +2.42° (c = 10 in H2O); +13.7° (c = 2.06 in 6N HCl)
Density: d 1.401
Derivative Type: D-Form
CAS Registry Number: 338-69-2
Literature References: Occurs in bacterial cell walls and in some peptide antibiotics. Review: M. Bodanszky, D. Perlman, Science 163, 352-358 (1969); C. T. Walsh, J. Biol. Chem. 264, 2393-2396 (1989).
Properties: Crystals, mp 289-291°. [a]D -14.1° (c = 0.9 in 1N HCl).
Melting point: mp 289-291°
Optical Rotation: [a]D -14.1° (c = 0.9 in 1N HCl)
Derivative Type: DL-Form
CAS Registry Number: 302-72-7
Properties: Orthorhombic bipyramidal needles or rods from water. d 1.424. Sublimes above 200°. Decomp 264-296° depending on rate of heating. pK1 2.35; pK2 9.87. Soly in water at 0°: 121 g/l, at 25°: 167 g/l, at 50°: 231 g/l, at 75°: 319 g/l, at 100°: 440 g/l; in ethanol 0.0087 g/100 g at 25°. Insol in ether.
pKa: pK1 2.35; pK2 9.87
Density: d 1.424
Alantolactone Alazopeptin Albaspidin Albendazole Albizziin

Structural formula of the L-isomer
Ball-and-stick model of the L-isomer
CAS number 338-69-2 (D-isomer) YesY, 56-41-7 (L-isomer), 302-72-7 (racemic)
PubChem 5950
ChemSpider 64234 (D-isomer) YesY, 5735 (L-isomer), 582 (Racemic)
EC-number 206-126-4
KEGG C01401 N
IUPHAR ligand 720
Jmol-3D images Image 1
Image 2
Molecular formula C3H7NO2
Molar mass 89.09 g mol−1
Appearance white powder
Density 1.424 g/cm3
Melting point 258 °C; 496 °F; 531 K (subl.)
Solubility in water 167.2 g/L (25 °C)
Acidity (pKa) 2.35 (carboxyl), 9.69 (amino)[1]
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

Alanine (abbreviated as Ala or A)[2] is an α-amino acid with 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 nonpolar amino acid. L-Alanine is second only to leucine in rate of occurrence, accounting for 7.8% of the primary structure in a sample of 1,150 proteins.[3] D-Alanine occurs in bacterial cell walls and in some peptide antibiotics.