Glutamate: a truly functional amino acid
Glutamate is one of the most abundant of the amino acids. In addition to its role in protein structure, it plays critical roles in nutrition, metabolism and signaling. Post-translational carboxylation of glutamyl residues increases their affinity for calcium and plays a major role in hemostasis. Glutamate is of fundamental importance to amino acid metabolism, yet the great bulk of dietary glutamate is catabolyzed within the intestine. It is necessary for the synthesis of key molecules, such as glutathione and the polyglutamated folate cofactors. It plays a major role in signaling. Within the central nervous system, glutamate is the major excitatory neurotransmitter and its product, GABA, the major inhibitory neurotransmitter. Glutamate interaction with specific taste cells in the tongue is a major component of umami taste. The finding of glutamate receptors throughout the gastrointestinal tract has opened up a new vista in glutamate function. Glutamate is truly a functional amino acid.
KeywordsGamma-carboxyglutamate GI tract Glutathione Insulin secretion Neurotransmitter Umami taste receptors
The authors’ work was supported by Canadian Institutes of Health Research.
Conflict of interest
- Höfer D, Püschel B, Drenckhahn (1996). Taste receptor-like cells in the rat gut identified by expression of alpha-gustducin. Proc Nat Acad Sci USA 93:6631–6634Google Scholar
- Matthews DE, Marano MA, Campbell RG (1993) Splanchnic bed utilization of glutamine and glutamic acid in humans. Am J Physiol 264:E848−E854Google Scholar
- Treberg et al (2009) On the reversibility of glutamate dehydrogenase and the source of hyperammonemia in the hyperinsulinism/hyperammonemia syndrome. Adv Enzym Regul 50:34–43Google Scholar
- Yasumatsu K, Ogiwara Y, Takai S, Yoshida R, Iwatsuki K, Torii K, Margolskee RF, Ninomiya Y (2011) Umami taste in mice use multiple receptors and transduction pathways. J Physiol (E pub)Google Scholar