2aminobutanedioic

2-aminobutanedioic acid, commonly known as aspartic acid, is one of the 20 standard amino acids used in protein synthesis. It is a non-essential amino acid in humans and can be synthesized in the body; the L-enantiomer is the form typically incorporated into proteins.

Chemically, it has the formula C4H7NO4 and a molar mass of about 133.10 g/mol. Its structure consists of a standard α-amino group attached to a four-carbon backbone with two carboxyl groups, giving it the full name 2-aminobutanedioic acid. At physiological pH it exists predominantly as a zwitterion, with the amino group protonated and both carboxyl groups deprotonated. The pKa values are approximately 2.10 for the α-carboxyl group, 3.86 for the side-chain carboxyl group, and 9.6–9.7 for the amino group.

Biologically, aspartate participates in several metabolic pathways. It can be transaminated to form oxaloacetate, linking to energy metabolism. It serves as a donor of the aspartate moiety in the formation of argininosuccinate in the urea cycle and is a precursor for the amino acid asparagine via asparagine synthetase. Aspartate also contributes to nucleotide biosynthesis, including pathways for pyrimidines and purines, and plays a role in amino acid metabolism and interconversion.

Occurrence and nutrition: aspartic acid is present in many proteins and is found in dietary sources such as meat, dairy products, eggs, and some plant foods. It is also a component in the synthesis of aspartame, an artificial sweetener formed from aspartic acid and phenylalanine methyl ester.