Glutamic acid together with its γ-monoamide – glutamine – makes up about a third of all free amino acids in blood plasma, its content in body proteins is 20-25 %. In the blood, glutamic acid maintains pH balance, binds excess ammonia, turning into glutamine, transports it to the site of detoxification, and serves as a reserve of amino groups. Glutamic acid acts as an excitatory neurotransmitter and agonist of all subtypes of glutamate receptors (metabotropic, kainate, NMDA and AMPA), and is also a precursor of gamma-aminobutyric acid (GABA). Glutamic acid has an immunomodulatory effect and affects many metabolic processes.