Mitochondrial glutamate dehydrogenase that converts L-glutamate into alpha-ketoglutarate. Plays a key role in glutamine anaplerosis by producing alpha-ketoglutarate, an important intermediate in the tricarboxylic acid cycle (By similarity). H2O + L-glutamate + NAD(+) = 2-oxoglutarate + H(+) + NADH + NH4(+) H2O + L-glutamate + NADP(+) = 2-oxoglutarate + H(+) + NADPH + NH4(+) Subject to allosteric regulation. Activated by ADP. Inhibited by GTP and ATP (By similarity). Optimum pH is 8.0. Optimum temperature is 30 degrees Celsius. Homohexamer. ADP can occupy the NADH binding site and activate the enzyme. Belongs to the Glu/Leu/Phe/Val dehydrogenases family.