<p><strong>Aspartic acid</strong> (abbreviated as <strong>Asp</strong> or <strong>D</strong>)<sup class="reference" id="_ref-0">[1]</sup> is an &alpha;-amino acid with the chemical formula HO₂CCH(NH₂)CH₂CO₂H. The L-isomer is a one of the 20 proteinogenic amino acids, i.e. the building blocks of proteins. Its codons are GAU and GAC. It is classified as an acidic amino acid, together with glutamic acid. Aspartic acid is pervasive in biosynthesis. Like all amino acids, the location of acid protons depends on the pH of the solution and the crystallization conditions.</p>

<p>The abbreviation Asx (or B) represent either aspartic acid or asparagine.</p>

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<h2><span class="mw-headline">Role in biosynthesis of amino acids</span></h2>