L-Aspartic acid

Aspartic acid (abbreviatedas D-AA, Asp, or D) is an α-amino acid with the chemical formulaHOOCCH(NH2)CH2COOH. The carboxylate anion and salts of aspartic acid are knownas aspartate. The L-isomer of aspartate is one of the 22 proteinogenic aminoacids, i.e., the building blocks of proteins. Its codons are GAU and GAC.

Aspartic acid is,together with glutamic acid, classified as an acidic amino acid with a pKa of3.9, however in a peptide the pKa is highly dependent on the local environment.A pKa as high as 14 is not at all uncommon. Aspartate is pervasive inbiosynthesis. As with all amino acids, the presence of acid protons depends onthe residue's local chemical environment and the pH of the solution.