Glutamate dehydrogenase is zinc, containing mitochondrial enzyme. GDH is controlled by allosteric regulation. ATP and GTP inhibit GDH, whereas ATP and GTP activate GDH.

Protein-rich diet: Glutamate level is elevated, which is converted to α-ketoglutarate with liberation of NH₃. When the energy levels are low, the dehydration of glutamate is increased to provide α-ketoglutarate, which enters TCA cycle to liberate energy.