Aspartic acid (aspartate) is an amino acid found in proteins. In mammals, aspartic acid is a non-essential amino acid, meaning it does not need to be present in the diet. Aspartic acid (surprise!) is classified as an acidic amino acid.

Aspartate is involved in the control point of pyrimidine biosynthesis (Reaction 1 below), in transamination reactions (Reaction 2 below), interconversions with asparagine (reactions 3 and 4), in the metabolic pathway leading to AMP (reaction 5 below), in the urea cycle (reactions 2 and 8 below), IMP de novo biosynthesis, and is a precursor to homoserine, threonine, isoleucine, and methionine (reaction 7 below). It is also involved in the malate aspartate shuttle.

One Letter Code	Three Letter Code	Molecular Wt. (Daltons)	Genetic Code Codons
D	ASP	115.09	GAU, GAC

Reactions involving Aspartic Acid

1. Aspartate + Carbamoyl Phosphate <=> Carbamoyl Aspartate (catalyzed by Aspartate Transcarbamoylase)

2. Oxaloacetate + Glutamate <-> Aspartate + -Ketoglutarate (catalyzed by Aminotransferase)

3. Aspartic Acid + ATP + NH3 (Gln) <=> Asparagine + AMP + PPi + Glutamate (catalyzed by Asparagine Synthetase - the enzyme strongly prefers to use the amine group of glutamine over that of free ammonia)

4. Glutamine + H2O <=> Aspartic Acid + NH3 (catalyzed by Asparaginase)

5. IMP + Aspartic Acid + GTP <=> Adenylosuccinate + GDP + Pi (catalyzed by Adenylosuccinate Synthetase)

6. CAIR + Aspartate + ATP <=> SACAIR + ADP + Pi (catalyzed by SACAIR Synthetase)

7. Aspartate + ATP <=> -Aspartyl-Phosphate + ADP (catalyzed by Aspartokinase)

8. Citrulline + Aspartate + ATP <=> Argininosuccinate + AMP + PPi (catalyzed by Argininosuccinate Synthetase).

1. Alanine Aspartate Metabolism

2. Urea Cycle and Metabolism of Amino Groups