Glutamic acid (${\mathrm{C}}_5{\mathrm{H}}_9\mathrm{N}{\mathrm{O}}_4$)

Glutamic acid is an amino acid with a second carboxylic acid group in its side chain. Near physiological pH, this side chain is mostly deprotonated, giving glutamate.

Transamination connects the glutamate carbon skeleton with 2-Oxoglutarate. This allows amino groups to be transferred between carbon skeletons, making glutamate central to nitrogen metabolism as well as a constituent of proteins.

Glutamate is an anionic form of glutamic acid, with one fewer proton. The acid and anion are different chemical species.