L-cysteic acid

L-cysteic acid is a non-proteinogenic sulfur-containing amino acid and the L-enantiomer of cysteic acid. It is an oxidation product of L-cysteine and features a C-terminal sulfonic acid group. Naturally occurring in human hair and sheep wool exposed to environmental factors, it serves as a metabolite in both humans and bacteria such as Escherichia coli[1][2]. In research settings, L-cysteic acid is used as an amino sulfonic acid derivative for peptide synthesis, biochemical studies on protein synthesis and enzyme activity, neuroscience investigations into neurotransmitter systems (notably as an agonist at several metabotropic glutamate receptors), and pharmaceutical development targeting oxidative stress or inflammation[4][5]. It also finds applications in food science for its antioxidant properties and in cosmetics for potential skin health benefits[4]. Mechanistically, it can act as a competitive inhibitor of the bacterial aspartate:alanine antiporter (AspT) and functions as an agonist at certain metabotropic glutamate receptors (mGluRs) in animal models[3][5].

Other names

L-cysteic acid(R)-2-amino-3-sulfopropanoic acid3-sulfo-L-alanine3-sulfo-L-alanine monohydratecysteic acid