glutamic

Glutamic, in most contexts, refers to glutamic acid and its related forms, including the anionic form glutamate. Glutamic acid is an α-amino acid that is one of the 20 standard amino acids used to build proteins. In its neutral form it has the chemical formula C5H9NO4, and in physiological conditions the molecule exists primarily as L-glutamate, either bound in proteins or as the free anion. Its side chain contains a carboxyl group, giving it acidic properties and a relatively low isoelectric point compared with some other amino acids.

Glutamic acid and its derivatives play important biological roles. Glutamate is the major excitatory neurotransmitter in the vertebrate central nervous system, acting on ionotropic receptors (NMDA, AMPA, and kainate) and metabotropic receptors to influence synaptic transmission, plasticity, learning, and memory. Beyond the nervous system, glutamate is a key donor of amino groups in amino acid metabolism and serves as a precursor for biosynthesis of other amino acids, nucleotides, and more. In cells, it is produced from α-ketoglutarate via transamination or reductive amination and can be converted to glutamine, GABA, or other metabolites as needed.

Glutamic acid is a common component of proteins in all organisms. The salt sodium glutamate (MSG) is widely used as a flavor enhancer in foods and is produced by fermentation. Regulatory agencies generally regard MSG as safe for the public at typical dietary levels, though a small number of individuals report adverse reactions, which remain a subject of study.