Aminomalonic acid (Ama) is an amino dicarboxylic acid that is an analog of malonic acid in which one of the methylene hydrogens has been replaced by an amino group. It is a strongly acidic compound that is very water soluble. Aminomalonic acid is a natural occurring, largely non-proteogenic amino acid that was first detected in alkaline hydrolysates of proteins in 1984. In particular, aminomalonic acid was isolated from proteins isolated from Escherichia coli cultures and from human atherosclerotic plaques (PMID: 6366787). Aminomalonic acid is a relatively unstable, minor amino acid in complex structures such as bacteria or tissues. The presence of aminomalonic acid has important biological implications because the malonic acid moiety potentially imparts calcium binding properties to proteins. Possible origins of aminomalonic acid in proteins include its introduction via errors in protein synthesis and oxidative damage to amino acid residues in proteins. (PMID: 1621954 , 6366787 ). Aminomalonic acid can be generated naturally via the activity of mammalian and bacterial enzymes on various precursors such as 2-aminomalonamide, diethylaminomalonate and ketomalonic acid (PMID: 35346). Free aminomalonic acid appears to be an oxidation product arising from perturbed serine or threonine metabolism. Aminomalonic acid is produced in animals that have been exposed to Cadmium (a strong pro-oxidant) for extended periods of time and it has been proposed to be a potential biomarker of Cadmium toxicity (PMID: 32193438). Aminomalonic acid has also been found to be elevated in the urine of individuals with anxiety and major depressive disorders (PMID: 30232320).  Aminomalonic acid has been reported to be a potential biomarker for hepatocellular carcinoma (PMID: 18767022) and it exhibits strong inhibitory effects on L-asparagine synthase (PMID: 35346). Several metabolomics studies have also found that altered aminomalonic acid levels in serum are associated with neuropsychiatric disorders, melanoma, ketamine overdose and aortic aneurysm, indicating that aminomalonic acid is an important serum indicator for diseases and toxicities (PMID: 32193438).