Reference
Aspartic Acid (Aspartate)
**Aspartic Acid (Aspartate)** is a nonessential amino acid that the human body synthesizes on its own, functioning as a building block of proteins and as a metabolic intermediate in the urea cycle and in the synthesis of nucleotides.
Structure and forms
Aspartic acid is one of the two acidic, negatively charged amino acids (the other is glutamic acid). At physiological pH its side-chain carboxyl group is deprotonated, so the residue carries a net negative charge — the reason it is usually referred to by its anionic form, aspartate. It occurs in two stereoisomers: L-aspartate, the form incorporated into proteins, and D-aspartate, found in smaller amounts in certain neuroendocrine tissues.
Because it is nonessential, aspartate does not need to be supplied by the diet. The body produces it primarily by transamination of oxaloacetate, a citric-acid-cycle intermediate, which links aspartate metabolism directly to energy production and nitrogen handling.
Metabolic roles
Aspartate is a nitrogen donor. In the urea cycle it supplies one of the two nitrogen atoms that end up in urea, the molecule the body uses to excrete excess nitrogen from protein breakdown. It is also a substrate for the synthesis of purine and pyrimidine nucleotides, the bases of DNA and RNA, and it participates in the malate–aspartate shuttle that moves reducing equivalents across the mitochondrial membrane. In the nervous system, aspartate acts as an excitatory neurotransmitter, though its role is smaller than that of glutamate.
Relevance to potato protein
Aspartate (often reported together with asparagine as “aspartic acid”) is among the more abundant amino acids in many plant proteins, including potato protein isolate. Because it is nonessential, it does not factor into protein-quality scores such as PDCAAS or DIAAS, which are calculated only from the indispensable amino acids. Potato protein isolate contains all nine essential amino acids, and the nonessential residues like aspartate contribute to its total nitrogen content and to its functional behavior in food. For broader background, see what potato protein is and how it is used.
In practical terms, the presence of aspartate matters less for muscle protein synthesis — which is driven by essential amino acids and leucine in particular — than for overall protein metabolism and nitrogen balance. It is one ingredient’s worth of biochemistry doing quiet, necessary work.
Related terms