Aspartic acid, also known as aspartate, the name of its anion, is one of the 20 natural proteinogenic amino acids which are the building blocks of proteins. As its name indicates, it is the carboxylic acid analog of asparagine. It is non-essential in mammals, and might serve as an excitatory neurotransmitter in the brain. It is also a metabolite in the urea cycle, and participates in gluconeogenesis.
Aspartic acid has a molecular weight of 133.10, a van der Waals radius of 91 and an isoelectric point of 2.85.
This neurotransmitter may provide resistance to fatigue and thus lead to possessing more endurance, although the evidence to support this idea is not strong.