Aspartic acid (or asparaginic acid) plays a vital role in metabolism while synthesizing other amino acids and metabolites in the citric acid cycle. Among the amino acids synthesized from aspartic acid are asparagine, arginine, lysine, methionine, threonine, isoleucine, and several nucleotides. Aspartic acid is also a metabolite in the urea cycle and participates in gluconeogenesis, generating glucose from non-sugar carbon substrates. Aspartic acid is alanine, and a carboxylic acid group replaces one of the beta-hydrogens.
The measurement of aspartic acid, along with 23 other amino acids, is included in the Amino Acids in Plasma and the Amino Acids in Urine tests.
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Aspartic acid (Asp/D) is the carboxylic acid analog of asparagine. As a neurotransmitter, aspartic acid may resist fatigue and thus lead to greater endurance, although not everyone supports this view. Aspartic acid is a non-essential amino acid made from glutamic acid by enzymes that use vitamin B6 as a coenzyme. The biosynthesis of aspartate is facilitated by an aminotransferase that catalyzes the transfer of an amino group from another molecule, such as alanine or glutamine and yields aspartic acid and an alpha-keto acid.
Aspartic acid plays a vital role in the urea cycle and DNA metabolism. It is also an important excitatory neurotransmitter, which is sometimes found elevated in patients with seizures and strokes. It is reduced in patients with depression and brain atrophy.
Magnesium and zinc may inhibit some of the actions of aspartic acid. Aspartic acid, along with the amino acid phenylalanine (and formaldehyde), is part of a new natural sweetener, aspartame. This sweetener is an advance on artificial sweeteners and is probably safe in regular doses in all but patients with phenylketonuria. However, studies on the long-term effects of aspartame on many of the brain's neuropeptides are still lacking.
Aspartic acid may be an essential thymus immunostimulant and may protect against some of the harmful effects of radiation. Supplementation with aspartic acid is relatively safe, and studies are being conducted to clarify its pharmacological and therapeutic roles.
Aspartic acid is found in high concentrations in animal products such as oysters, meat, and meat products (sausages, etc.), and plant products such as grains (mainly sprouts), oats, avocados, asparagus, sugarcane, and sugar beet molasses.
